:Boeing 737

File:1964 Boeing 737 concept.png

Boeing had been studying short-haul jet aircraft designs, and saw a need for a new aircraft to supplement the 727 on short and thin routes."[https://www.nytimes.com/1964/07/17/transport-news-boeing-plans-jet.html Transport News: Boeing Plans Jet.] {{Webarchive|url=https://web.archive.org/web/20170821213438/http://www.nytimes.com/1964/07/17/transport-news-boeing-plans-jet.html |date=August 21, 2017}}" The New York Times, July 17, 1964. Retrieved: February 26, 2008. Preliminary design work began on May 11, 1964,{{sfn|Endres|2001|p=122|ps=}} based on research that indicated a market for a fifty to sixty passenger airliner flying routes of {{Convert|50|to|1000|mi|-2}}.{{sfn|Sharpe|Shaw|2001|p=12|ps=}}

The initial concept featured podded engines on the aft fuselage, a T-tail as with the 727, and five-abreast seating. Engineer Joe Sutter relocated the engines to the wings which lightened the structure and simplified the accommodation of six-abreast seating in the fuselage. The engine nacelles were mounted directly to the underside of the wings, without pylons, allowing the landing gear to be shortened, thus lowering the fuselage to improve baggage and passenger access.{{sfn|Sutter|2006|pp=76–78}} Relocating the engines from the aft fuselage also allowed the horizontal stabilizer to be attached to the aft fuselage instead of as a T-tail.{{sfn|Sharpe |Shaw|2001|p=17|ps=}} Many designs for the engine attachment strut were tested in the wind tunnel and the optimal shape for high speed was found to be one which was relatively thick, filling the narrow channels formed between the wing and the top of the nacelle, particularly on the outboard side.File:Boeing 737 patent USD206035S.jpg for Boeing]]

At the time, Boeing was far behind its competitors; the SE 210 Caravelle had been in service since 1955, and the BAC One-Eleven (BAC-111), Douglas DC-9, and Fokker F28 were already into flight certification. To expedite development, Boeing used 60% of the structure and systems of the existing 727, particularly the fuselage, which differs in length only. This 148-inch (3.76 m) wide fuselage cross-section permitted six-abreast seating compared to the rivals' five-abreast. The 727's fuselage was derived from the 707.{{sfn|Sharpe|Shaw|2001|p=13|ps=}}

The proposed wing airfoil sections were based on those of the 707 and 727, but somewhat thicker; altering these sections near the nacelles achieved a substantial drag reduction at high Mach numbers.Olason, M.L. and Norton, D.A. "Aerodynamic Philosophy of the Boeing 737", AIAA paper 65-739, presented at the AIAA/RAeS/JSASS Aircraft Design and Technology Meeting, Los Angeles California, November 1965. Reprinted in the AIAA Journal of Aircraft, Vol. 3 No. 6, November/December 1966, pp. 524–528. The engine chosen was the Pratt & Whitney JT8D-1 low-bypass ratio turbofan engine, delivering {{Convert|14500|lbf|kN|lk=on}} of thrust.{{sfn|Shaw|1999|p=6|ps=}}

The concept design was presented in October 1964 at the Air Transport Association maintenance and engineering conference by chief project engineer Jack Steiner, where its elaborate high-lift devices raised concerns about maintenance costs and dispatch reliability.{{cite news |url= https://www.flightglobal.com/news/articles/analysis-half-century-milestone-marks-737s-endurin-435787/ |title= Half-century milestone marks 737's enduring appeal |date= April 7, 2017 |author= Stephen Trimble |work= FlightGlobal}}

File:Boeing 737 family v1.0.png

The original 737 continued to be developed into thirteen passenger, cargo, corporate and military variants. These were later divided into what has become known as the four generations of the Boeing 737 family:

• The first generation "Original" series: the 737-100 and -200, also the military T-43 and CT-43, launched February 1965.
• The second generation "Classic" series: 737-300, -400 and -500, launched in 1979.
• The third generation "Next Generation" series: 737-600, -700, -800 and -900, also the military C-40 and P-8, launched late 1993.
• The fourth generation 737 MAX series: 737-7, -8, -9 and -10, launched August 2011.

The launch decision for the $150 million (~${{Format price|{{Inflation|index=US-GDP|value=150000000|start_year=1965}}}} in {{Inflation/year|US-GDP}}) development was made by the board on February 1, 1965.{{sfn|Sharpe|Shaw|2001|p=13|ps=}} The sales pitch was big-jet comfort on short-haul routes.{{cite web |last1=Thomas |first1=Geoffrey |title=Boeing's 737: The plane that almost never was. |url=https://www.airlineratings.com/news/boeings-737-the-plane-that-almost-never-was/ |website=Airline Ratings |access-date=June 3, 2023 |language=en-AU |date=April 23, 2017}}

Lufthansa became the launch customer on February 19, 1965,{{sfn|Sharpe|Shaw|2001|p=13|ps=}} with an order for 21 aircraft, worth $67 million (~${{Format price|{{Inflation|index=US-GDP|value=67000000|start_year=1965}}}} in {{Inflation/year|US-GDP}})"German Airline Buys 21 Boeing Short-Range Jets." The Washington Post, February 20, 1965. Retrieved: February 26, 2008. after the airline had been assured by Boeing that the 737 project would not be canceled.Wallace, J. [http://www.seattlepi.com/default/article/Boeing-delivers-its-5-000th-737-1195654.php "Boeing delivers its 5,000th 737."] {{Webarchive|url=https://web.archive.org/web/20120309074239/http://www.seattlepi.com/default/article/Boeing-delivers-its-5-000th-737-1195654.php |date=March 9, 2012}} Seattle Post-Intelligencer, February 13, 2006. Retrieved June 7, 2011. Consultation with Lufthansa over the previous winter had resulted in the seating capacity being increased to 100.{{sfn|Sharpe|Shaw|2001|p=13|ps=}}

On April 5, 1965, Boeing announced an order by United Airlines for 40 737s. United wanted a slightly larger capacity than the 737-100, so the fuselage was stretched {{Convert|91|cm|order=flip}} ahead of, and {{Convert|102|cm|order=flip}} behind the wing.{{sfn|Sharpe|Shaw|2001|p=17|ps=}} The longer version was designated the 737-200, with the original short-body aircraft becoming the 737-100.{{sfn|Redding|Yenne|1997|p=182|ps=}} Detailed design work continued on both variants simultaneously.

File:Boeing 737-130, Lufthansa AN2056613.jpg

The first -100 was rolled out on January 17, 1967, and took its maiden flight on April 9, 1967, piloted by Brien Wygle and Lew Wallick.{{cite web|title=Original 737 Comes Home to Celebrate 30th Anniversary|url=http://boeing.mediaroom.com/1997-05-02-Original-737-Comes-Home-to-Celebrate-30th-Anniversary|website= boeing.com|publisher=Boeing|access-date=November 18, 2014|date=May 2, 1997|archive-date=November 29, 2014|archive-url=https://web.archive.org/web/20141129031351/http://boeing.mediaroom.com/1997-05-02-Original-737-Comes-Home-to-Celebrate-30th-Anniversary|url-status=live}} After several test flights the Federal Aviation Administration (FAA) issued Type Certificate A16WE certifying the 737-100 for commercial flight on December 15, 1967.{{sfn|Sharpe|Shaw|2001|p=20|ps=}}[http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/e038ae3ed2dbc2ae86257479004d1e57/$FILE/A16WE.pdf "Type Certificate Data Sheet A16WE."] {{Webarchive|url=https://web.archive.org/web/20080909234057/http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/e038ae3ed2dbc2ae86257479004d1e57/$FILE/A16WE.pdf |date=September 9, 2008}} faa.gov. Retrieved: September 3, 2010. It was the first aircraft to have, as part of its initial certification, approval for Category II approaches,{{sfn|Redding|Yenne|1997|p=183|ps=}} which refers to a precision instrument approach and landing with a decision height between {{Convert|30|and|60|m|ft|order=flip}}.{{cite news |last1=Williams |first1=Scott |title=CAT II – Category II – Approach |url=https://aviationglossary.com/cat-ii-category-ii-approach/ |website=Aviation Glossary |access-date=October 30, 2018 |date=January 18, 2009 |archive-date=October 31, 2018 |archive-url=https://web.archive.org/web/20181031005411/https://aviationglossary.com/cat-ii-category-ii-approach/ |url-status=live}} Lufthansa received its first aircraft on December 28, 1967, and on February 10, 1968, became the first non-American airline to launch a new Boeing aircraft.{{sfn|Sharpe|Shaw|2001|p=20|ps=}} Lufthansa was the only significant customer to purchase the 737-100 and only 30 aircraft were produced.{{sfn|Sharpe|Shaw|2001|p=120|ps=}}

The -200 was rolled out on June 29, 1967, and had its maiden flight on August 8, 1967. It was then certified by the FAA on December 21, 1967.{{sfn|Endres|2001|p=124|ps=}} The inaugural flight for United Airlines took place on April 28, 1968, from Chicago to Grand Rapids, Michigan.{{sfn|Sharpe|Shaw|2001|p=20|ps=}} The lengthened -200 was widely preferred over the -100 by airlines.{{cite web |url=http://modernairliners.com/boeing-737/boeing-737-history |title=Boeing 737 History |publisher=ModernAirlines.com |access-date=August 10, 2015 |date=July 29, 2015 |archive-date=August 22, 2015 |archive-url=https://web.archive.org/web/20150822194856/http://modernairliners.com/boeing-737/boeing-737-history |url-status=live}} The improved version, the 737-200 Advanced, was introduced into service by All Nippon Airways on May 20, 1971.{{sfn|Bowers|1989|p=496|ps=}}

The 737 original model with its variants, known later as the Boeing 737 Original, initially competed with SE 210 Caravelle and BAC-111 due to their earlier entry into service and later primarily with the McDonnell Douglas DC-9, then its MD-80 derivatives as the three European short-haul single aisles slowly withdrew from the competition. Sales were low in the early 1970s{{cite news |last1=Podsada |first1=Janice |title=Small local suppliers flying blind through 737 Max crisis |url=https://www.heraldnet.com/business/small-local-suppliers-flying-blind-through-737-max-crisis/ |access-date=January 17, 2020 |work=The Everett Herald |date=January 11, 2020 |archive-date=January 17, 2020 |archive-url=https://web.archive.org/web/20200117014533/https://www.heraldnet.com/business/small-local-suppliers-flying-blind-through-737-max-crisis/ |url-status=live}} and, after a peak of 114 deliveries in 1969, only 22 737s were shipped in 1972 with 19 in backlog. The US Air Force saved the program by ordering T-43s, which were modified Boeing 737-200s. African airline orders kept the production running until the 1978 US Airline Deregulation Act, which improved demand for six-abreast narrow-body aircraft. Demand further increased after being re-engined with the CFM56. The 737 went on to become the highest-selling commercial aircraft in terms of orders until surpassed by the competing Airbus A320 family in October 2019, but maintains the record in total deliveries.{{Cite web|last=Slotnick|first=David|title=Boeing's 737 officially lost the title of world's most popular airplane. Airbus' competitor just passed it in sales.|url=https://www.businessinsider.com/airbus-beats-worlds-most-popular-plane-a320-737-2019-11|access-date=October 18, 2021|website=Business Insider|language=en-US}}

The fuselage is manufactured in Wichita, Kansas, by Boeing spin-off company Spirit AeroSystems, before being moved by rail to Renton.[https://www.railwayage.com/freight/bnsf-mrl-move-10000th-boeing-737-fuselage/?RAchannel=news BNSF, MRL move 10,000th Boeing 737 fuselage] {{Webarchive|url=https://web.archive.org/web/20191103185122/https://www.railwayage.com/freight/bnsf-mrl-move-10000th-boeing-737-fuselage/?RAchannel=news |date=November 3, 2019}} Railway Age February 20, 2018 The Renton factory has three assembly lines for the 737 MAX; a fourth is planned to open at the Everett factory in 2024.{{cite news |last=Gates |first=Dominic |date=January 30, 2023 |title=Boeing to set up a new 737 MAX assembly line in Everett |url=https://www.seattletimes.com/business/boeing-aerospace/boeing-to-set-up-a-fourth-737-max-assembly-line-in-everett/ |work=The Seattle Times |accessdate=July 18, 2023}}

{{anchor|737 Original}}

The Boeing 737 Original is the name given to the -100 and -200 series of the Boeing 737 family. These are sometimes referred to by the nickname 737 Jurassic,{{cite web|url=https://leehamnews.com/2020/01/27/pontifications-back-to-drawing-board-on-nma-boeings-ceo-says/|title=Pontifications: Back to drawing board on NMA, Boeing’s CEO says|work=Leeham News and Analysis|date=January 27, 2020|last=Hamilton|first=Scott|access-date=April 3, 2025}} including by Boeing itself.{{cite web archived|title=Boeing 737 Facts|url=http://www.boeing.com/commercial/737family/facts.html|archive-date=2012-03-28|publisher=Boeing|date=September 30, 2011}}

File:Lufthansa Boeing 737-100 in Zurich 1981.jpg Boeing 737-100 at Zurich Airport in 1981]]

The initial model was the 737-100, the smallest variant of the 737 aircraft family, which was launched in February 1965 and entered service with Lufthansa in February 1968. In 1968, its unit cost was {{US dollar|3600000|1968|link=Yes|round=-5}}.{{cite magazine |url= http://archive.aviationweek.com/issue/19680122#!&pid=30 |title= 737 price raised |magazine= Aviation Week |date= January 22, 1968 |page= 31 |url-access= subscription |access-date= October 14, 2018 |archive-date= October 15, 2018 |archive-url= https://web.archive.org/web/20181015002825/http://archive.aviationweek.com/issue/19680122#!&pid=30 |url-status= live}} A total of just 30 737-100s were produced: 22 for Lufthansa, 5 for Malaysia–Singapore Airlines (MSA) and 2 for Avianca with the final aircraft delivered to MSA on October 31, 1969. This variant was largely overshadowed by its bigger 737-200 sibling, which entered service two months later.

The original engine nacelles incorporated thrust reversers taken from the 727 outboard nacelles. They proved to be relatively ineffective and tended to lift the aircraft up off the runway when deployed. This reduced the downforce on the main wheels thereby reducing the effectiveness of the wheel brakes. In 1968, an improvement to the thrust reversal system was introduced.{{sfn|Sharpe|Shaw|2001|p=[https://archive.org/details/boeing737100200a00mich/page/21 21]|ps=}} A 48-inch tailpipe extension was added and new target-style thrust reversers were incorporated. The thrust reverser doors were set 35 degrees away from the vertical to allow the exhaust to be deflected inboard and over the wings and outboard and under the wings. The improvement became standard on all aircraft after March 1969, and a retrofit was provided for active aircraft. Longer nacelle/wing fairings were introduced, and the airflow over the flaps and slats was improved. The production line also introduced an improvement to the flap system, allowing increased use during takeoff and landing. All these changes gave the aircraft a boost to payload and range, and improved short-field performance.{{sfn|Sharpe|Shaw|2001|p=20|ps=}}

Both the first and last 737-100s became the last 737-100s in service. The first aircraft used by Boeing as prototype under registration N73700 was later ordered by and delivered to NASA on July 26, 1973, which then operated it under registration N515NA and retired after 30 years on September 27, 2003. The last 737-100 built and also the last operating was originally sold to MSA, transferred to Air Florida, before being used as a VIP aircraft by the Mexican Air Force for 23 years under registration TP-03.{{Citation needed|date=September 2024}} TP-03 would be broken up in 2006. The first 737-100, NASA 515, is on static display in the Museum of Flight in Seattle and is the last surviving example of the type.{{sfn|Shaw|1999|p=8|ps=}}

File:United 737-200 N3013U at CLE (17159967836).jpg. The -200 was one of the most popular variants sold, with 1095 units.]]

The 737-200 was a 737-100 with an extended fuselage, launched by an order from United Airlines in 1965 and entered service with the launch customer in April 1968. Its unit cost was US$4.0M (1968) (${{Inflation|US|4.0|r=1|1968}}M today). The -200's unit cost was US$5.2M (1972){{cite magazine |url= https://www.flightglobal.com/pdfarchive/view/1972/1972%20-%202020.html |title= Airliner price index |magazine= Flight International |date= August 10, 1972 |page= 183 |access-date= January 9, 2018 |archive-date= January 9, 2018 |archive-url= https://web.archive.org/web/20180109181149/https://www.flightglobal.com/pdfarchive/view/1972/1972%20-%202020.html |url-status= live}} (${{Inflation|US|5.2|r=1|1972}}M today). The 737-200 Advanced is an improved version of the -200, introduced into service by All Nippon Airways on May 20, 1971.{{sfn|Bowers|1989|p=496|ps=}} After aircraft #135, the 737-200 Advanced has improved aerodynamics, automatic wheel brakes, more powerful engines, more fuel capacity, and hence a 15% increase in payload and range over the original -200s and respectively -100s.{{sfn|Redding|Yenne|1997|p=183|ps=}}{{sfn|Sharpe|Shaw|2001|p=41|ps=}} The 737-200 Advanced became the production standard in June 1971.{{cite web |url= http://www.boeing.com/assets/pdf/commercial/airports/acaps/737.pdf |title= 737 Airplane Characteristics for Airport Planning |date= May 2011 |publisher= Boeing |access-date= February 7, 2015 |archive-date= February 7, 2015 |archive-url= https://web.archive.org/web/20150207152159/http://www.boeing.com/assets/pdf/commercial/airports/acaps/737.pdf |url-status= live}} Boeing also provided the 737-200C (Combi), which allowed for conversion between passenger and cargo use and the 737-200QC (Quick Change), which facilitated a rapid conversion between roles. The 1,114th{{cite web |author1=The Boeing Company |title=Boeing Commercial Orders & Deliveries |url=https://public.tableau.com/app/profile/salesoperations/viz/shared/CMD3CKDC8 |website=Tableau Public |access-date=6 August 2024 |format=Filtered data table }} and last delivery of a -200 series aircraft was in August 1988 to Xiamen Airlines.[http://www.boeing.com/commercial/737family/background.html "About the 737 Family."] {{Webarchive|url=https://web.archive.org/web/20041209163449/http://www.boeing.com/commercial/737family/background.html |date=December 9, 2004}} The Boeing Company. Retrieved: December 20, 2007.

Nineteen 737-200s, designated T-43, were used to train aircraft navigators for the U.S. Air Force. Some were modified into CT-43s, which are used to transport passengers, and one was modified as the NT-43A Radar Test Bed. The first was delivered on July 31, 1973, and the last on July 19, 1974. The Indonesian Air Force ordered three modified 737-200s, designated Boeing 737-2X9 Surveiller. They were used as Maritime reconnaissance (MPA)/transport aircraft, fitted with SLAMMAR (Side-looking Multi-mission Airborne Radar). The aircraft were delivered between May 1982 and October 1983.{{sfn|Bowers|1989|pp=498–499|ps=}}After 40 years, in March 2008, the final 737-200 aircraft in the U.S. flying scheduled passenger service were phased out, with the last flights of Aloha Airlines.{{cite web|url=http://swamedia.com/releases/Southwest-Airlines-Retires-Last-of-Founding-Aircraft-Employees-Help-Celebrate-the-Boeing-737-200-s-Final-Flight?mode=print |title=Southwest Airlines Retires Last of Founding Aircraft; Employees Help Celebrate the Boeing 737-200's Final Flight |publisher=swamedia.com |access-date=August 27, 2015 |url-status=dead |archive-url=https://web.archive.org/web/20150904131052/http://swamedia.com/releases/Southwest-Airlines-Retires-Last-of-Founding-Aircraft-Employees-Help-Celebrate-the-Boeing-737-200-s-Final-Flight?mode=print |archive-date=September 4, 2015}} As of 2018, the variant still saw regular service through North American charter operators such as Sierra Pacific Airlines.{{Cite web|url=https://www.flightglobal.com/asset/24536|title=World Airline Census 2018|website=Flightglobal.com|language=en-GB|access-date=August 21, 2018|archive-date=November 6, 2018|archive-url=https://web.archive.org/web/20181106212640/https://www.flightglobal.com/asset/24536|url-status=live}}

File:C-GANV landing in Vancouver.jpg 737-200 fitted with a gravel kit.]]

The short-field capabilities of the 737-200 led Boeing to offer the "Unpaved Strip Kit" (see the Air North example, right). This option reduced foreign object damage when operated on remote, unimproved or unpaved runways, that competing jetliners could not use safely. The kit included a gravel deflector on the nose gear and a vortex dissipator extending from the front of the engine. Alaska Airlines used the gravel kit for some of its combi aircraft rural operations in Alaska until retiring its -200 fleet in 2007.{{cite web|title=The Airplane That Never Sleeps|url=http://boeing.mediaroom.com/2002-07-15-The-Airplane-That-Never-Sleeps|publisher=Boeing|access-date=November 19, 2014|date=July 15, 2002|archive-date=November 29, 2014|archive-url=https://web.archive.org/web/20141129033740/http://boeing.mediaroom.com/2002-07-15-The-Airplane-That-Never-Sleeps|url-status=live}}{{Cite news |url=https://www.wsj.com/articles/SB117642845035668637 |title=Arctic Eagles Bid Mud Hens Farewell At Alaska Airlines |last=Carey |first=Susan |date=April 13, 2007 |work=The Wall Street Journal |access-date=February 7, 2015 |archive-date=February 7, 2015 |archive-url=https://web.archive.org/web/20150207152612/http://www.wsj.com/articles/SB117642845035668637 |url-status=live}} Air Inuit, Nolinor Aviation and Chrono Aviation still use the gravel kit in Northern Canada.

Canadian North also operated a gravel-kitted 737-200 Combi, but this was due to be retired in early 2023.[https://www.ch-aviation.com/portal/news/122390-canadian-north-to-retire-last-b737-200-in-early-2q23 ch-aviation.com – Canadian North to retire last B737-200 in early 2Q23] December 13, 2022

{{as of|2023|09}}, a relatively high number of 737-200s remain in service compared to other early jet airliners, with fifty examples actively flying for thirty carriers.{{Cite web |last=Chen |first=Andrew |date=September 1, 2023 |title=Where Are Boeing 737-200s Flying in 2023? |url=https://airlinegeeks.com/2023/09/01/where-are-boeing-737-200s-flying-in-2023/ |access-date=September 23, 2023 |website=AirlineGeeks.com |language=en}} During the 737 MAX groundings, older 737s, including the 200 and Classic series, were in demand for leasing.{{cite web |last=LeBeau |first=Phil |title=Airlines hurt by the 737 Max grounding are scrambling to find replacement jets |url=https://www.cnbc.com/2019/08/09/airlines-hurt-by-737-max-grounding-are-scrambling-to-find-replacements.html |website=CNBC |date=August 9, 2019 |access-date=January 16, 2024}} C-GNLK, one of Nolinor's 737-200s, is the oldest jet airliner in commercial service as of 2024, having entered service 50 years prior in 1974.{{Citation needed|date=December 2024|reason=This is an unsupported superlative, though it may be true.}}

{{main|Boeing 737 Classic}}

The Boeing 737 Classic is the name given to the 737-300/400/500 series after the introduction of the -600/700/800/900 series of the Boeing 737 family.{{cite web |url= http://www.boeing.com/boeing/commercial/737family/facts.page |title= Boeing: Boeing 737 Facts |date= September 6, 2013 |access-date= February 7, 2015 |publisher= Boeing |archive-date= February 15, 2015 |archive-url= https://web.archive.org/web/20150215183442/http://www.boeing.com/boeing/commercial/737family/facts.page |url-status= live}} Produced from 1984 to 2000, a total of 1,988 Classic series were delivered.{{sfn|Endres|2001|p=129|ps=}}

Close to the next major upgrade of single aisle aircraft at Airbus and Boeing, the price of jet fuel reached a peak in 2008, when airlines devoted 40% of the retail price of an air ticket to pay for fuel, versus 15% in 2000."To Save Fuel, Airlines Find No Speck Too Small." The New York Times, June 11, 2008.{{cite web |title=Jet Fuel Price Development |url=http://www.iata.org/publications/economics/fuel-monitor/Pages/price-development.aspx |publisher=IATA |access-date=April 10, 2015 |archive-date=April 11, 2015 |archive-url=https://web.archive.org/web/20150411084634/http://www.iata.org/publications/economics/fuel-monitor/Pages/price-development.aspx |url-status=live}} Consequently, in that year carriers retired Boeing 737 Classic aircraft to reduce fuel consumption; replacements consisted of more efficient 737 Next Generation or A320 family aircraft. On June 4, 2008, United Airlines announced it would retire all 94 of its Classic 737 aircraft (64 737-300 and 30 737-500 aircraft), replacing them with A320 family jets taken from its Ted subsidiary, which has been shut down."UAL Cuts Could Be Omen." The Wall Street Journal, June 5, 2008, p. B3.{{cite web |author1=David Grossman |date=June 29, 2000 |title=Why Ted's demise is a boost for business travelers |website=USA Today |url=http://usatoday30.usatoday.com/travel/columnist/grossman/2008-06-27-demise-of-ted_N.htm |access-date=November 19, 2014 |archive-date=October 16, 2015 |archive-url=https://web.archive.org/web/20151016201845/http://usatoday30.usatoday.com/travel/columnist/grossman/2008-06-27-demise-of-ted_N.htm |url-status=live}}"Airline Shares Gain Despite Losses." The Wall Street Journal, July 23, 2008, p. B3. This intensified the competition between the two giant aircraft manufacturers, which has since become a duopoly competition.

An optional upgrade with winglets became available for the Classic and NG series.

• The 737-300 and 737-500 can be retrofitted with Aviation Partners Boeing winglets, and the 737-300 retrofitted with winglets is designated the -300SP (Special Performance).
• WestJet was to launch the 737-600 with winglets, but dropped them in 2006.{{cite web |url= http://www.boeing.com/commercial/737family/winglets/index.html |title= Next-Generation 737 Production Winglets |publisher= Boeing|archive-url= https://web.archive.org/web/20080428073227/http://www.boeing.com/commercial/737family/winglets/index.html |archive-date= April 28, 2008}}

File:N513AU in Florida, 1991.jpg.]]

Development began in 1979 for the 737's first major revision, which was originally introduced as the 'new generation' of the 737.{{sfn|Shaw|1999|p=7|ps=}} Boeing wanted to increase capacity and range, incorporating improvements to upgrade the aircraft to modern specifications, while also retaining commonality with previous 737 variants. In 1980, preliminary aircraft specifications of the variant, dubbed 737-300, were released at the Farnborough Airshow.{{sfn|Endres|2001|p=126|ps=}} This first major upgrade series was later renamed 737 Classic. It competed primarily with the MD-80, its later derivative the MD-90, and the newcomer Airbus A320 family.

Boeing engineer Mark Gregoire led a design team, which cooperated with CFM International to select, modify and deploy a new engine and nacelle that would make the 737-300 into a viable aircraft. They chose the CFM56-3B-1 high-bypass turbofan engine to power the aircraft, which yielded significant gains in fuel economy and a reduction in noise, but also posed an engineering challenge, given the low ground clearance of the 737 and the larger diameter of the engine over the original Pratt & Whitney engines. Gregoire's team and CFM solved the problem by reducing the size of the fan (which made the engine slightly less efficient than it had been forecast to be), placing the engine ahead of the wing, and by moving engine accessories to the sides of the engine pod, giving the engine a distinctive non-circular "hamster pouch" air intake.{{sfn|Endres|2001|p=128|ps=}}Sweetman, Bill, All mouth, Air & Space, September 2014, p.14 Earlier customers for the CFM56 included the U.S. Air Force with its program to re-engine KC-135 tankers.{{sfn|Garvin |1998|p=137}}

The passenger capacity of the aircraft was increased to 149 by extending the fuselage around the wing by {{Convert|2.87|m|ftin|sp=us|order=flip}}. The wing incorporated several changes for improved aerodynamics. The wingtip was extended {{Convert|9|in|cm}}, and the wingspan by {{Convert|1|ft|9|in|cm}}. The leading-edge slats and trailing-edge flaps were adjusted.{{sfn|Endres|2001|p=128|ps=}} The tailfin was redesigned, the flight deck was improved with the optional EFIS (Electronic Flight Instrumentation System), and the passenger cabin incorporated improvements similar to those developed on the Boeing 757.{{sfn|Shaw|1999|p=10|ps=}} The prototype -300, the 1,001st 737 built, first flew on February 24, 1984, with pilot Jim McRoberts.{{sfn|Shaw|1999|p=10|ps=}} It and two production aircraft flew a nine-month-long certification program.{{sfn|Shaw|1999|pp=12–13|ps=}} The 737-300 retrofitted with Aviation Partners' winglets was designated the -300SP (Special Performance). The 737-300 was replaced by the 737-700 of the Next Generation series.

File:Boeing 737-401, Piedmont Airlines AN0203147.jpg]]

The 737-400 was launched in 1985 to fill the gap between the 737-300 and the 757-200. In June 1986, Boeing announced the development of the 737-400,{{sfn|Redding|Yenne|1997|p=185|ps=}} which stretched the fuselage a further {{Convert|10|ft}}, increasing the capacity to 188 passengers, and requiring a tail bumper to prevent tailstrikes during take-off and a strengthened wing spar.{{cite report |title=FAA Type Certificate Data Sheet A16WE |url=http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/9c59427a20b3253686257d03004d8faa/$FILE/A16WE_Rev_53.pdf |publisher=Department of Transportation, Federal Aviation Administration |date= |access-date=July 8, 2015 |archive-date=December 25, 2016 |archive-url=https://web.archive.org/web/20161225060513/http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/9c59427a20b3253686257d03004d8faa/$FILE/A16WE_Rev_53.pdf |url-status=live}} The -400s first flight was on February 19, 1988, and, after a seven-month/500-hour flight-testing run, entered service with Piedmont Airlines that October.{{sfn|Shaw|1999|p=14|ps=}} The last two -400s, i.e. the last 737 Classics series, were delivered to CSA Czech Airlines on February 28, 2000.{{cite press release |url= https://boeing.mediaroom.com/2000-02-28-Boeing-Delivers-737-400s-to-CSA-Czech-Airlines |title= Boeing Delivers 737-400s to CSA Czech Airlines |date= February 28, 2000 |publisher= Boeing |access-date= August 30, 2020 |archive-date= September 15, 2020 |archive-url= https://web.archive.org/web/20200915173112/https://boeing.mediaroom.com/2000-02-28-Boeing-Delivers-737-400s-to-CSA-Czech-Airlines |url-status= live}} The 737-400 was replaced by the 737-800 of the Next Generation series. The 737-400SF was a 737-400 converted to freighter, though it was not a model delivered by Boeing and hence the nickname Special Freighter (SF). Alaska Airlines was the first to convert one of their 400s from regular service to an aircraft with the ability to handle 10 pallets.{{cite web |url=http://www.alaskaair.com/content/travel-info/fleet/737-400-freighter.aspx |title=Boeing 737-400 Freighter |work=Aircraft Information |publisher=Alaska Airlines |access-date=June 29, 2011 |archive-date=January 22, 2014 |archive-url=https://web.archive.org/web/20140122165843/https://www.alaskaair.com/content/travel-info/fleet/737-400-freighter.aspx |url-status=live}} The airline had also converted five more into fixed combi aircraft for half passenger and freight. These 737-400 Combi aircraft were retired in 2017 and replaced by the 737-700F of the Next Generation series.{{Cite news|url=https://blog.alaskaair.com/alaska-airlines/fleet/combi-plane-retires/|title=The end of an era: Alaska retires unique cargo-passenger 'combi' planes|date=October 16, 2017|work=Alaska Airlines Blog|access-date=July 26, 2018|language=en-US|archive-date=March 26, 2019|archive-url=https://web.archive.org/web/20190326170156/https://blog.alaskaair.com/alaska-airlines/fleet/combi-plane-retires/|url-status=live}}

File:Boeing 737-500 (Southwest Airlines) (2389306174).jpg 737-500 landing in Las Vegas in 2008]]

The 737-500 was offered as a modern and direct replacement of the 737-200. It was launched in 1987 by Southwest Airlines, with an order for 20 aircraft,{{sfn|Shaw|1999|p=40|ps=}} and it flew for the first time on June 30, 1989.{{sfn|Shaw|1999|p=14|ps=}} A single prototype flew 375 hours for the certification process,{{sfn|Shaw|1999|p=14|ps=}} and on February 28, 1990, Southwest Airlines received the first delivery.{{sfn|Endres|2001|p=129|ps=}}

The -500 incorporated the improvements of the 737 Classic series, allowing longer routes with fewer passengers to be more economical than with the 737-300. The fuselage length of the 737-500 is {{Convert|1|ft|7|in|cm}} longer than the 737-200, accommodating up to 140 passengers. Both glass and older-style mechanical cockpits arrangements were available.{{sfn|Shaw|1999|p=14|ps=}} Using the CFM56-3 engine also gave a 25 percent increase in fuel efficiency over the older 737-200s P&W engines.{{sfn|Shaw|1999|p=14|ps=}}

The 737-500 has faced accelerated retirement due to its smaller size, after 21 years in service compared to 24 years for the -300.{{cite news|url=https://airwaysmag.com/airchive/southwest-retires-final-boeing-737-500/|title=Southwest Retires Final Boeing 737-500|work=Aircraft Information|date=September 7, 2016 |publisher=Airways Magazine|access-date=August 30, 2020|archive-date=March 7, 2021|archive-url=https://web.archive.org/web/20210307231717/https://airwaysmag.com/airchive/southwest-retires-final-boeing-737-500/|url-status=live}} While a few 737-300s were slated for freighter conversion, no demand at all existed for a -500 freighter conversion. The 737-500 was replaced by the 737-600 of the Next Generation series, though the -600 was not as successful in total orders as the -500.

{{main|Boeing 737 Next Generation}}

The Boeing 737 Next Generation, abbreviated as 737 Next Gen or 737NG, is the name given to the -600, -700, -800 and -900 variants. It has been produced since 1996 and introduced in 1997, with a total order of 7,097 aircraft, of which 7,031 have been delivered {{as of|2019|May|df=|lc=y}}. The primary goal was to re-engine the 737 with the high bypass ratio CFM56-7. By the early 1990s, as the MD-80 slowly withdrew from the competition following the introduction of the MD-90, it had become clear that the new A320 family was a serious threat to Boeing's market share. Airbus won previously loyal 737 customers, such as Lufthansa and United Airlines. In November 1993, to stay in the single aisle competition, Boeing's board of directors authorized the Next Generation program to mainly upgrade the 737 Classic series.[http://www.boeing.com/commercial/737family/pf/pf_ng_milestones.html "Next Generation 737 Program Milestones."] {{Webarchive|url=https://web.archive.org/web/20080125233751/http://www.boeing.com/commercial/737family/pf/pf_ng_milestones.html |date=January 25, 2008}} The Boeing Company. Retrieved: January 22, 2008. In late 1993, after engineering trade studies and discussions with major customers, Boeing proceeded to launch a second derivative of the Boeing 737, the 737 Next Generation (NG) -600/700/800/900 series. It featured a redesigned wing with a wider wingspan and larger area, greater fuel capacity, longer range and higher MTOWs. It was equipped with CFM56-7 high pressure ratio engines, a glass cockpit, and upgraded interior configurations. The four main models of the series can accommodate seating for 108 to 215 passengers. It was further developed into additional versions such as the corporate Boeing Business Jet (BBJ) and military P-8 Poseidon aircraft. Following the merger between Boeing with McDonnell Douglas in 1997, the primary competitor for the 737NG series remained only the A320 family.

File:Sas b737-600 ln-rcw arp.jpg, the launch customer]]

The 737-600 was the smallest of the Next-Generation models, replacing the 737-500. It had no winglets and was similar in size to the Airbus A318. Launch customer Scandinavian Airlines (SAS) placed its order in March 1995 and took the first delivery in September 1998.{{cite news |url= https://www.flightglobal.com/news/articles/putting-the-family-to-work-51106/ |title= Putting the family to work |date= May 12, 1999 |magazine= Flight International |author= Andrew Doyle |author2= Max Kingsley-Jones |author3= Paul Lewis |author4= Guy Norris |access-date= June 11, 2018 |archive-url= https://web.archive.org/web/20180612145307/https://www.flightglobal.com/news/articles/putting-the-family-to-work-51106/ |archive-date= June 12, 2018 |url-status= live}} A total of 69 aircraft were produced, with the last one delivered to WestJet in 2006.

File:N785SW BWI MD1.jpg, the launch customer]]

The 737-700, the first variant of the Next-Generation, was launched in November 1993 with an order of 63 aircraft. The -700 seats 126 passengers in a two-class or 149 passengers in a one-class layout. Launch customer Southwest Airlines took the first delivery in December 1997.{{cite press release |url= http://boeing.mediaroom.com/1997-12-17-First-Boeing-737-700-Goes-to-Southwest-Airlines |title= First Boeing 737-700 Goes to Southwest Airlines |date= December 17, 1997 |publisher= Boeing |access-date= June 11, 2018 |archive-url= https://web.archive.org/web/20180609005014/http://boeing.mediaroom.com/1997-12-17-First-Boeing-737-700-Goes-to-Southwest-Airlines |archive-date= June 9, 2018 |url-status= live}} The 737-700 replaced the 737-300 and competes with the Airbus A319.

The 737-700C is a convertible version where the seats can be removed to carry cargo instead. There is a large door on the left side of the aircraft. The United States Navy was the launch customer for the 737-700C under the military designation C-40 Clipper.[http://www.defenselink.mil/releases/release.aspx?releaseid=2647 "U.S. Naval Reserve Gets First Look at Newest Class of Aircraft"] {{Webarchive|url=https://web.archive.org/web/20080527061741/http://www.defenselink.mil/releases/release.aspx?releaseid=2647 |date=May 27, 2008}}. DefenseLink (U.S. Department of Defense). Retrieved January 21, 2008.

The 737-700ER (Extended Range) was launched on January 31, 2006, and featured the fuselage of the 737-700 and the wings and landing gear of the 737-800. A 737-700ER can typically accommodate 126 passengers in two classes with a range similar to the Airbus A319LR.{{cite press release |url= http://boeing.mediaroom.com/2007-02-16-Boeing-Delivers-First-737-700ER-to-Launch-Customer-ANA |title= Boeing Delivers First 737-700ER to Launch Customer ANA |publisher= Boeing |date= February 16, 2007 |access-date= June 11, 2018 |archive-url= https://web.archive.org/web/20180612141757/http://boeing.mediaroom.com/2007-02-16-Boeing-Delivers-First-737-700ER-to-Launch-Customer-ANA |archive-date= June 12, 2018 |url-status= live}}

File:D-ATUF B737-8K5W TUIfly-Hapag retro PMI 26SEP10 (6341092368).jpg, the launch customer]]

The 737-800 was a stretched version of the 737-700 launched on September 5, 1994, and first flew on July 31, 1997.{{cite press release|url=https://boeing.mediaroom.com/1997-07-31-Longest-Boeing-737-Makes-First-Flight|date=July 31, 1997|access-date=January 14, 2025|publisher=Boeing|title=Longest Boeing 737 Makes First Flight}} The -800 seats 162 passengers in a two-class or 189 passengers in a high-density, one-class layout. Launch customer Hapag-Lloyd Flug (now TUIfly) received the first one in April 1998.{{cite press release |url= https://boeing.mediaroom.com/1998-04-23-First-Boeing-Next-Generation-737-800-Goes-To-Hapag-Lloyd |title= First Boeing Next-Generation 737-800 Goes To Hapag-Lloyd |date= April 23, 1998 |publisher= Boeing |access-date= September 5, 2020 |archive-date= September 15, 2020 |archive-url= https://web.archive.org/web/20200915184844/https://boeing.mediaroom.com/1998-04-23-First-Boeing-Next-Generation-737-800-Goes-To-Hapag-Lloyd |url-status= live}} The 737-800 replaced directly the -400 and aging 727-200 of US airlines. It filled also the gap left by Boeing's decision to discontinue the MD-80 and MD-90 aircraft, following Boeing's merger with McDonnell Douglas. The 737-800 is the most widely used narrowbody aircraft and competes primarily with the Airbus A320.{{cite web|url=https://www.mro-network.com/airframe/boeing-737-800-not-expected-peak-until-2021|title=Inside MRO: Boeing 737-800 Not Expected To Peak Until 2021|last=Derber|first=Alex|work=MRO Network |date=June 14, 2018|publisher=Aviation Week & Space Technology|access-date=August 17, 2018|archive-url=https://web.archive.org/web/20180818052311/https://www.mro-network.com/airframe/boeing-737-800-not-expected-peak-until-2021|archive-date=August 18, 2018|url-status=live}}

File:Lionair 737-900 ER first flight.jpg on the vertical stabilizer. The added exit door is visible aft of the wing.]]

The 737-900 was launched in November 1997 and took its first flight on August 3, 2000.{{cite press release|url=https://boeing.mediaroom.com/1997-11-10-Alaska-Airlines-Order-Launches-Boeing-737-900-Program|title=Alaska Airlines Order Launches Boeing 737-900 Program|date=November 10, 1997|publisher=Boeing|access-date=January 14, 2025}}{{cite press release|url=https://boeing.mediaroom.com/2000-08-03-Boeing-Next-Generation-737-900-Takes-First-Flight|title=Boeing Next-Generation 737-900 Takes First Flight|date=August 3, 2000|publisher=Boeing|access-date=January 14, 2025}} It is longer than the -800, but retains the MTOW, fuel capacity, and exit configuration of the -800, essentially trading range for capacity. The exit configuration limits its seat capacity to approximately 177 in a two class and 189 in a high-density, one class layout. Launch customer Alaska Airlines received the first delivery on May 2001.{{cite press release|url=https://boeing.mediaroom.com/2001-05-16-Alaska-Airlines-Receives-First-Boeing-737-900|date=May 16, 2001|title=Alaska Airlines Receives First Boeing 737-90|access-date=January 14, 2025|publisher=Boeing}}

The 737-900ER (Extended Range), the newest and largest variant of the 737NG generation, was launched in July 2005, first flew in September 2006, and first delivered to launch customer Lion Air in April 2007.{{cite news|url=https://www.flightglobal.com/boeing-performs-first-flight-of-737-900er-extended-range-737/69437.article|last=Reals|first=Kerry|date=September 5, 2006|access-date=January 14, 2025|title=Boeing performs first flight of 737-900ER, extended range 737|publisher=FlightGlobal}}{{cite press release|url=https://boeing.mediaroom.com/2007-04-27-Boeing-Delivers-First-737-900ER-to-Launch-Customer-Lion-Air|title=Boeing Delivers First 737-900ER to Launch Customer Lion Air|date=April 27, 2007|access-date=January 14, 2025|publisher=Boeing}} An additional pair of exit doors and a flat rear pressure bulkhead increased its seating capacity to 180 passengers in a two-class and up to 220 passengers in a one-class configuration.{{cite web|url=http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/9dd07e4b4293722e86257dfc006774ca/$FILE/A16WE_Rev_54.pdf|title=FAA Type Certificate Data Sheet|access-date=July 1, 2015|archive-url=https://web.archive.org/web/20161225060506/http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/9dd07e4b4293722e86257dfc006774ca/$FILE/A16WE_Rev_54.pdf|archive-date=December 25, 2016|url-status=live}}

The -900ER partly closed the gap left by the discontinuation of the Boeing 757-200, and directly competes with the Airbus A321.{{Cite web |last=Schofield |first=Adrian |date=July 20, 2005 |title=Boeing's 737-900ER Seen As Direct Competitor To A321 |url=http://www.aviationweek.com/aw/generic/story_generic.jsp?channel=aviationdaily&id=news/739B07205.xml |url-status=dead |archive-url=https://web.archive.org/web/20120322021345/http://www.aviationweek.com/aw/generic/story_generic.jsp?channel=aviationdaily&id=news%2F739B07205.xml |archive-date=March 22, 2012 |access-date=July 3, 2015 |website=Aviation Week & Space Technology}}

{{main|Boeing 737 MAX}}

The Boeing 737 MAX is the name given to the main models 737 MAX 7/8/9/10 series and the higher-density MAX 200 variant of the Boeing 737 family. It is offered in four main variants, typically offering 138 to 230 seats and a range of {{Convert|3,215|to|3,825|nmi|abbr=~|lk=in}}. The 737 MAX 7, MAX 8 (including the denser, 200-seat MAX 200), and MAX 9 replace the 737-700, -800, and -900 respectively. The further stretched 737 MAX 10 has also been added to the series. The aim was to re-engine the 737NG family using CFM LEAP-1B engines having very high bypass ratio, to compete with the Airbus A320neo family. On July 20, 2011, Boeing announced plans for a third major upgrade and respectively fourth generation of 737 series to be powered by the CFM LEAP-1B engine, with American Airlines intending to order 100 of these aircraft.{{cite press release |url= https://boeing.mediaroom.com/2011-07-20-Boeing-and-American-Airlines-Agree-on-Order-for-up-to-300-Airplanes |title= Boeing and American Airlines Agree on Order for up to 300 Airplanes |publisher= Boeing |date= July 20, 2011 |access-date= February 26, 2020 |archive-date= May 15, 2013 |archive-url= https://web.archive.org/web/20130515174119/http://boeing.mediaroom.com/index.php?s=43&item=1845 |url-status= live}}

On August 30, 2011, Boeing confirmed the launch of the 737 new engine variant, to be called the Boeing 737 MAX.{{cite press release |url= http://boeing.mediaroom.com/index.php?item=1907 |title= Boeing Launches 737 New Engine Family with Commitments for 496 Airplanes from Five Airlines |publisher= Boeing |date= August 30, 2011 |access-date= August 30, 2011 |archive-date= March 25, 2012 |archive-url= https://web.archive.org/web/20120325125301/http://boeing.mediaroom.com/index.php?item=1907 |url-status= live}}{{cite news |url= https://www.flightglobal.com/boeing-officially-launches-re-engined-737/101830.article |title= Boeing officially launches re-engined 737 |work= Flightglobal |date= August 30, 2011 |access-date= February 26, 2020 |archive-date= February 26, 2020 |archive-url= https://web.archive.org/web/20200226074024/https://www.flightglobal.com/boeing-officially-launches-re-engined-737/101830.article |url-status= live}}{{cite news |author= Guy Norris |title= Boeing Board Gives Go-Ahead To Re-Engined 737 |url= http://aviationweek.com/awin/boeing-board-gives-go-ahead-re-engined-737 |work= Aviation Week |date= August 30, 2011|archive-url= https://web.archive.org/web/20170804230502/http://aviationweek.com/awin/boeing-board-gives-go-ahead-re-engined-737 |archive-date= August 4, 2017}} It was based on earlier 737 designs with more efficient LEAP-1B power plants, aerodynamic improvements (most notably split-tip winglets), and airframe modifications. It competes with the Airbus A320neo family that was launched in December 2010 and reached 1,029 orders by June 2011, breaking Boeing's monopoly with American Airlines, which had an order for 130 A320neos that July.{{cite news |url= https://www.nytimes.com/2011/07/21/business/global/american-places-record-order-with-2-jet-makers.html |title= American Orders 460 Narrow Jets from Boeing and Airbus |work= The New York Times |date= July 20, 2011 |access-date= August 24, 2017 |archive-date= June 18, 2018 |archive-url= https://web.archive.org/web/20180618203630/https://www.nytimes.com/2011/07/21/business/global/american-places-record-order-with-2-jet-makers.html |url-status= live}} The 737 MAX had its first flight on January 29, 2016, and gained FAA certification on March 8, 2017.{{cite web |url=http://www.seattletimes.com/business/boeing-aerospace/boeings-737-max-takes-off-on-first-flight/ |title=Boeing's 737 MAX takes wing with new engines, high hopes |date=January 29, 2016 |work=The Seattle Times |access-date=September 8, 2018 |archive-date=April 9, 2019 |archive-url=https://web.archive.org/web/20190409134614/https://www.seattletimes.com/business/boeing-aerospace/boeings-737-max-takes-off-on-first-flight/ |url-status=live}}{{cite web |url= http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/0970d54d00efbb9a862580de006a83cc/$FILE/A16WE_Rev_58.pdf |title= Type Certificate Data Sheet No. A16WE |date= March 8, 2017 |publisher= FAA |access-date= September 8, 2018 |archive-date= November 13, 2017 |archive-url= https://web.archive.org/web/20171113165744/http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/0970d54d00efbb9a862580de006a83cc/$FILE/A16WE_Rev_58.pdf |url-status= live}} The first delivery was a MAX 8 on May 6, 2017, to Lion Air's subsidiary Malindo Air,{{cite news |url= https://www.flightglobal.com/news/articles/boeing-delivers-first-737-max-437289/ |title= Boeing delivers first 737 Max |date= May 16, 2017 |author= Stephen Trimble |work= Flightglobal |access-date= September 8, 2018 |archive-date= December 29, 2018 |archive-url= https://web.archive.org/web/20181229205216/https://www.flightglobal.com/news/articles/boeing-delivers-first-737-max-437289/ |url-status= live}} which put it into service on May 22, 2017.{{cite news |url=https://www.flightglobal.com/news/articles/malindo-operates-worlds-first-737-max-flight-437454/ |title=Malindo operates world's first 737 Max flight |author=Hashim Firdaus |date=May 22, 2017 |work=FlightGlobal |access-date=August 19, 2017 |archive-date=November 13, 2018 |archive-url=https://web.archive.org/web/20181113205531/https://www.flightglobal.com/news/articles/malindo-operates-worlds-first-737-max-flight-437454/ |url-status=live}} {{as of|2019|January}}, the series has received 5,011 firm orders.

In March 2019, civil aviation authorities around the world grounded the 737 MAX following two hull loss crashes which caused 346 deaths.{{Cite news|url=https://www.nytimes.com/2019/03/13/business/canada-737-max.html|title=Trump Announces Ban of Boeing 737 Max Flights|last1=Austen|first1=Ian|date=March 13, 2019|work=The New York Times|last2=Gebrekidan|first2=Selam|access-date=January 3, 2020|archive-date=September 13, 2019|archive-url=https://web.archive.org/web/20190913163144/https://www.nytimes.com/2019/03/13/business/canada-737-max.html|url-status=live}} On December 16, 2019, Boeing announced that it would suspend production of the 737 MAX from January 2020,{{cite press release |url= https://boeing.mediaroom.com/2019-12-16-Boeing-Statement-Regarding-737-MAX-Production |title= Boeing Statement Regarding 737 MAX Production |date= December 16, 2019 |publisher= Boeing |access-date= January 9, 2020 |archive-date= December 17, 2019 |archive-url= https://web.archive.org/web/20191217161043/https://boeing.mediaroom.com/2019-12-16-Boeing-Statement-Regarding-737-MAX-Production |url-status= live}} which was resumed in May 2020. In the midyear 2020, the FAA and Boeing conducted a series of recertification test flights.{{cite web |title=FAA Updates on Boeing 737 MAX |url=https://www.faa.gov/news/updates/?newsId=93206 |website=www.faa.gov |access-date=July 2, 2020 |date=July 1, 2020 |archive-date=September 1, 2019 |archive-url=https://web.archive.org/web/20190901092700/https://www.faa.gov/news/updates/?newsId=93206 |url-status=live}} On November 18, 2020, the FAA cleared the MAX to return to service. Before the aircraft can fly again, repairs must be implemented and airlines' training programs must be approved. Passenger flights in the U.S. are expected to resume before the end of the year.{{cite news |last1=Gates |first1=Dominic |url=https://www.seattletimes.com/business/boeing-aerospace/boeing-737-max-can-return-to-the-skies-says-faa/ |work=Seattle Times|date=November 18, 2020 |title=Boeing 737 MAX can return to the skies, FAA says |access-date=November 18, 2020 |archive-date=November 30, 2020 |archive-url=https://web.archive.org/web/20201130042530/https://www.seattletimes.com/business/boeing-aerospace/boeing-737-max-can-return-to-the-skies-says-faa/ |url-status=live}} Worldwide, the first airline to resume passenger service was Brazilian low-cost Gol, on December 9, 2020.{{cite news |title=Boeing 737 Max: Brazilian airline resumes passenger flights |url=https://www.bbc.com/news/world-latin-america-55243961 |work=BBC News |date=December 9, 2020 |access-date=December 9, 2020 |archive-date=December 9, 2020 |archive-url=https://web.archive.org/web/20201209142253/https://www.bbc.com/news/world-latin-america-55243961 |url-status=live}}

File:Boeing Company, N7201S, Boeing 737-7 MAX (30416417438).jpg

The 737 MAX 7, a shortened variant of the MAX 8, was originally based on the 737-700, flying {{Convert|1,000|nmi}} farther and accommodating two more seat rows at 18% lower fuel costs per seat.{{cite news |url= https://airwaysmag.com/industry/boeing-737-max-sparkles-as-max-7-5-10x-loom/ |title= Farnborough: Boeing's Execution on 737 MAX Sparkles as MAX 7.5 and MAX 10X Loom |work= Airways Magazine |date= July 10, 2016 |access-date= September 6, 2020 |archive-date= July 11, 2016 |archive-url= https://web.archive.org/web/20160711115643/https://airwaysmag.com/industry/boeing-737-max-sparkles-as-max-7-5-10x-loom/ |url-status= live}}{{cite news |url= https://www.flightglobal.com/news/articles/farnborough-boeing-confirms-737-max-7-redesign-427190/ |title= Boeing confirms 737 Max 7 redesign |publisher= FlightGlobal |date= July 11, 2016 |access-date= September 6, 2020 |archive-date= November 29, 2019 |archive-url= https://web.archive.org/web/20191129034102/https://www.flightglobal.com/news/articles/farnborough-boeing-confirms-737-max-7-redesign-427190/ |url-status= live}} The redesign uses the 737-8 wing and landing gear; a pair of over-wing exits rather than the single-door configuration; a {{Convert|46|in|mm|adj=mid|-longer}} aft fuselage and a {{Convert|30|in|mm|adj=mid|-longer}} longer forward fuselage; structural re-gauging and strengthening; and systems and interior modifications to accommodate the longer length.{{cite web |url= http://www.ainonline.com/aviation-news/air-transport/2016-07-12/boeing-upscales-737-700 |title= Boeing Upscales 737-700 |work= Aviation International News |date= July 12, 2016 |access-date= September 6, 2020 |archive-date= May 27, 2021 |archive-url= https://web.archive.org/web/20210527120649/https://www.ainonline.com/aviation-news/aerospace/2016-07-12/boeing-upscales-737-max-7 |url-status= live}} Entry into service with launch operator Southwest Airlines was originally expected in January 2019, but certification delays have pushed this back, with Boeing CEO David Calhoun saying certification was possible in the first half of 2025.{{cite news |url= https://www.flightglobal.com/news/articles/boeing-starts-building-first-737-max-7-441830/ |title= Boeing starts building first 737 Max 7 |date= October 4, 2017 |first= Stephen |last= Trimble |publisher= FlightGlobal |access-date= September 6, 2020 |archive-date= May 10, 2019 |archive-url= https://web.archive.org/web/20190510153352/https://www.flightglobal.com/news/articles/boeing-starts-building-first-737-max-7-441830/ |url-status= live}}{{cite news |url= https://www.flightglobal.com/news/articles/southwest-converts-options-for-40-more-737-max-8s-444563/ |title= Southwest converts options for 40 more 737 Max 8s |date= January 2, 2018 |first= Ghim-Lay |last= Yeo |publisher= FlightGlobal |access-date= September 6, 2020 |archive-date= April 9, 2019 |archive-url= https://web.archive.org/web/20190409131120/https://www.flightglobal.com/news/articles/southwest-converts-options-for-40-more-737-max-8s-444563/ |url-status= live}}{{Cite web|last=Hemmerdinger|first=Jon|url=https://www.flightglobal.com/airframers/boeing-ceo-sees-path-to-certificating-max-7-and-10-in-first-half-of-2025/159433.article|access-date=January 13, 2025|website=Flight Global|title=Boeing CEO sees path to certificating Max 7 and 10 in first half of 2025}} The 737 MAX 7 replaced the 737-700 and was predicted to carry 12 more passengers and fly {{Convert|400|nmi}} farther than the competing Airbus A319neo with 7% lower operating costs per seat.{{cite news |url= http://aviationweek.com/new-civil-aircraft/boeing-begins-737-7-flight-test-program |title= Boeing Begins 737-7 Flight Test Program |date= March 16, 2018 |first= Guy |last= Norris |work= Aviation Week Network |access-date= September 6, 2020 |archive-date= October 17, 2018 |archive-url= https://web.archive.org/web/20181017221034/http://aviationweek.com/new-civil-aircraft/boeing-begins-737-7-flight-test-program |url-status= live}}

File:9M-LRD (37495597164).jpg livery), the launch customer]]

The 737 MAX 8, the first variant of the 737 MAX, has a longer fuselage than the MAX 7. On July 23, 2013, Boeing completed the firm configuration for the 737 MAX 8.[http://boeing.mediaroom.com/2013-07-23-Boeing-Completes-737-MAX-8-Firm-Configuration "Boeing Completes 737 MAX 8 Firm Configuration"] {{Webarchive|url=https://web.archive.org/web/20150923052701/http://boeing.mediaroom.com/2013-07-23-Boeing-Completes-737-MAX-8-Firm-Configuration |date=September 23, 2015}}. Boeing, July 23, 2013. Its first commercial flight was operated by Malindo Air on May 22, 2017. The MAX 8 replaced the 737-800 and competed with the A320neo.

The 737 MAX 200, a high-density version of the 737 MAX 8, was launched in September 2014 and named for seating for up to 200 passengers in a single-class layout with slimline seats requiring an extra pair of exit doors. The MAX 200 would be 20% more cost-efficient per seat, including 5% lower operating costs than the MAX 8 and would be the most efficient narrow-body on the market when entering service.{{cite press release |title= Boeing Launches 737 MAX 200 with Ryanair |url= http://boeing.mediaroom.com/2014-09-08-Boeing-Launches-737-MAX-200-with-Ryanair |publisher= Boeing |date= September 8, 2014 |access-date= September 6, 2020 |archive-date= September 9, 2014 |archive-url= https://web.archive.org/web/20140909004548/http://boeing.mediaroom.com/2014-09-08-Boeing-Launches-737-MAX-200-with-Ryanair |url-status= live}} In mid-November 2018, the first MAX 200 of the 135 ordered by Ryanair rolled out, in a 197-seat configuration.{{cite news |last1=Noëth |first1=Bart |title=Ryanair's first Boeing 737 MAX 200 aircraft has rolled out of Boeing's final assembly line |url=https://www.aviation24.be/airlines/ryanair/first-boeing-737-max-200-aircraft-rolled-out-boeing-final-assembly-line/ |work=Aviation24.be |date=November 19, 2018 |access-date=September 6, 2020 |archive-date=August 17, 2020 |archive-url=https://web.archive.org/web/20200817201156/https://www.aviation24.be/airlines/ryanair/first-boeing-737-max-200-aircraft-rolled-out-boeing-final-assembly-line/ |url-status=live}} It was first flown from Renton on January 13, 2019, and was due to enter service in April 2019.{{cite news |url= http://aviationweek.com/awincommercial/first-high-capacity-boeing-737-8-enters-flight-test |title= First High-Capacity Boeing 737-8 Enters Flight Test Jan 23, 2019 Guy Norris |work= Aviation Week Network |access-date= September 6, 2020 |archive-date= January 26, 2019 |archive-url= https://web.archive.org/web/20190126163514/http://aviationweek.com/awincommercial/first-high-capacity-boeing-737-8-enters-flight-test |url-status= live}}{{cite news |last1=Clark |first1=Oliver |title=Ryanair Max to make debut at Stansted |url=https://www.flightglobal.com/news/articles/ryanair-max-to-make-debut-at-stansted-455782/ |publisher=FlightGlobal |date=February 14, 2019 |access-date=September 6, 2020 |archive-date=November 29, 2019 |archive-url=https://web.archive.org/web/20191129034052/https://www.flightglobal.com/news/articles/ryanair-max-to-make-debut-at-stansted-455782/ |url-status=live}}

File:Boeing, N7379E, Boeing 737-9 MAX (cropped).jpg

The 737 MAX 9, the stretched variant of the MAX 8, was launched with an order of 201 aircraft in February 2012. It made its roll-out on March 7, 2017, and first flight on April 13, 2017;{{cite news |url= http://www.seattletimes.com/business/boeing-aerospace/boeings-737-max-9-ready-for-first-flight-thursday/ |title= Boeing's 737 MAX 9 takes off on first flight |date= April 13, 2017 |newspaper= The Seattle Times |access-date= September 6, 2020 |archive-date= August 18, 2020 |archive-url= https://web.archive.org/web/20200818071518/https://www.seattletimes.com/business/boeing-aerospace/boeings-737-max-9-ready-for-first-flight-thursday/ |url-status= live}} It was certified by February 2018.{{cite news |url= https://www.flightglobal.com/news/articles/boeing-737-max-9-receives-certification-445995/ |title= Boeing 737 Max 9 receives certification |date= February 16, 2018 |first= Stephen |last= Trimble |publisher= FlightGlobal |access-date= September 6, 2020 |archive-date= May 10, 2019 |archive-url= https://web.archive.org/web/20190510153424/https://www.flightglobal.com/news/articles/boeing-737-max-9-receives-certification-445995/ |url-status= live}} The launch customer, Lion Air Group, took the first MAX 9 on March 21, 2018, before entering service with Thai Lion Air.{{cite press release |url= http://boeing.mediaroom.com/2018-03-21-Boeing-Delivers-First-737-MAX-9 |title= Boeing Delivers First 737 MAX 9 |date= March 21, 2018 |publisher= Boeing |access-date= September 6, 2020 |archive-date= September 11, 2020 |archive-url= https://web.archive.org/web/20200911160746/https://boeing.mediaroom.com/2018-03-21-Boeing-Delivers-First-737-MAX-9 |url-status= live}} The 737 MAX 9 replaced the 737-900 and competes with the Airbus A321neo.

File:737 MAX 10 Roll Out (Nov 2019) - 003.jpg

The 737 MAX 10 was proposed as a stretched MAX 9 in mid-2016, enabling seating for 230 in a single class or 189 in two-class layout, compared to 193 in two-class seating for the A321neo. The modest {{Convert|66|in|m|adj=on|abbr=out}} stretch of fuselage enables the MAX 10 to retain the existing wing and CFM Leap 1B engine from the MAX 9 with a trailing-link main landing gear as the only major change.{{cite news |url= http://aviationweek.com/technology/boeing-defines-final-737-max-stretch-offering |title= Boeing Defines Final 737 MAX Stretch Offering |date= January 10, 2017 |first= Guy |last= Norris |work= Aviation Week & Space Technology |access-date= September 6, 2020 |archive-date= January 31, 2017 |archive-url= https://web.archive.org/web/20170131222215/http://aviationweek.com/technology/boeing-defines-final-737-max-stretch-offering |url-status= live}} The MAX 10 was launched on June 19, 2017, with 240 orders and commitments from more than ten customers.{{cite news |url= https://www.flightglobal.com/news/articles/paris-boeing-launches-737-max-10-438370/ |title= Boeing launches 737 Max 10 |date= June 19, 2017 |first= Stephen |last= Trimble |publisher= Flightglobal |access-date= September 6, 2020 |archive-date= May 10, 2019 |archive-url= https://web.archive.org/web/20190510153358/https://www.flightglobal.com/news/articles/paris-boeing-launches-737-max-10-438370/ |url-status= live}} The variant configuration with a predicted 5% lower trip cost and seat cost compared to the A321neo was firmed up by February 2018, and by mid-2018, the critical design review was completed.{{cite news |url= http://www.boeingblogs.com/randy/archives/2017/03/max_10x_1.html |title= MAX 10X |first= Randy |last= Tinseth |date= March 6, 2017 |publisher= Boeing |access-date= September 6, 2020 |archive-date= November 26, 2017 |archive-url= https://web.archive.org/web/20171126185251/http://www.boeingblogs.com/randy/archives/2017/03/max_10x_1.html |url-status= live}}{{cite press release |url= http://boeing.mediaroom.com/2018-02-06-Boeing-737-MAX-10-Reaches-Firm-Configuration |title= Boeing 737 MAX 10 Reaches Firm Configuration |date= February 6, 2018 |publisher= Boeing |access-date= September 6, 2020 |archive-date= September 19, 2020 |archive-url= https://web.archive.org/web/20200919105022/https://boeing.mediaroom.com/2018-02-06-Boeing-737-MAX-10-Reaches-Firm-Configuration |url-status= live}} The MAX 10 has a similar capacity to the A321XLR, but shorter range and much poorer field performance in smaller airports.{{cite news |title=Why the A321XLR makes sense for Alaska Airlines |url=https://leehamnews.com/2020/02/23/why-the-a321xlr-makes-sense-for-alaska-airlines/ |access-date=February 24, 2020 |work=Leeham News and Analysis |date=February 23, 2020 |archive-date=March 12, 2021 |archive-url=https://web.archive.org/web/20210312173432/https://leehamnews.com/2020/02/23/why-the-a321xlr-makes-sense-for-alaska-airlines/ |url-status=live}} It was unveiled in Boeing's Renton factory on November 22, 2019, and first flew on June 18, 2021.{{cite press release |url= https://boeing.mediaroom.com/news-releases-statements?item=130578 |title= Boeing 737 MAX 10 Makes its Debut |date= November 22, 2019 |publisher= Boeing |access-date= September 6, 2020 |archive-date= September 15, 2020 |archive-url= https://web.archive.org/web/20200915173156/https://boeing.mediaroom.com/news-releases-statements?item=130578 |url-status= live}}{{cite news |url=https://www.chicagotribune.com/business/chi-boeing-new-airplane-20141105-story.html |title=Boeing plans to develop new airplane to replace 737 Max by 2030 |date=November 5, 2014 |work=Chicago Tribune |url-status=live |archive-url= https://web.archive.org/web/20141112215116/http://www.chicagotribune.com/business/breaking/chi-boeing-new-airplane-20141105-story.html |archive-date=November 12, 2014}}{{Cite news |last=Hemmerdinger |first=Jon |date=June 18, 2021 |title=Boeing 737 Max 10 makes maiden flight |work=Flight Global |url=https://www.flightglobal.com/airframers/boeing-737-max-10-makes-maiden-flight/144230.article |url-status=live |access-date=June 18, 2021 |archive-url=https://web.archive.org/web/20210627215105/https://www.flightglobal.com/airframers/boeing-737-max-10-makes-maiden-flight/144230.article |archive-date=June 27, 2021}} The MAX 10 is still awaiting certification, with Boeing CEO David Calhoun saying in July 2024 that the MAX 10 could be certified in the first half of 2025.

In the late 2010s, Boeing worked on a medium-range Boeing New Midsize Airplane (NMA) with two variants seating 225 or 275 passengers and targeting the same market segment as the 737 MAX 10 and the Airbus A321neo.{{cite news |url= http://aviationweek.com/commercial-aviation/boeing-still-lot-be-decided-nma |title= Boeing: Still 'A Lot' To Be Decided On NMA |date= February 7, 2018 |author= Michael Bruno |work= Aviation Week Network |access-date= January 24, 2020 |archive-date= October 10, 2018 |archive-url= https://web.archive.org/web/20181010094223/http://aviationweek.com/commercial-aviation/boeing-still-lot-be-decided-nma |url-status= live}} A Future Small Airplane (FSA) was also touted during this period.{{cite news |title=Boeing's NMA in doubt as airlines take fresh look at 737 Max & 757 replacement |url=https://theaircurrent.com/aircraft-development/boeings-nma-in-doubt-as-airlines-take-fresh-look-at-737-max-757-replacement/ |work=The Air Current |date=October 28, 2019 |access-date=January 24, 2020 |archive-date=October 30, 2019 |archive-url=https://web.archive.org/web/20191030072027/https://theaircurrent.com/aircraft-development/boeings-nma-in-doubt-as-airlines-take-fresh-look-at-737-max-757-replacement/ |url-status=live}} The NMA project was set aside in January 2020, as Boeing focused on returning the 737 MAX to service and announced that it would be taking a new approach to future projects.{{cite news |url= https://www.flightglobal.com/air-transport/boeing-to-take-another-clean-sheet-to-nma-with-focus-on-pilots/136296.article |title= Boeing to take another 'clean sheet' to NMA with focus on pilots |author= Jon Hemmerdinger |date= January 23, 2020 |work= flightglobal |access-date= January 24, 2020 |archive-date= January 25, 2020 |archive-url= https://web.archive.org/web/20200125100748/https://www.flightglobal.com/air-transport/boeing-to-take-another-clean-sheet-to-nma-with-focus-on-pilots/136296.article |url-status= live}}

The 737 continued to evolve into many variants but still remains recognizable as the 737. These are divided into four generations but all are based on the same basic design.

The fuselage cross section and nose are derived from that of the Boeing 707 and Boeing 727. Early 737 cockpits also inherited the "eyebrow windows" positioned above the main glareshield, which were a feature of the original 707 and 727{{cite web |url=http://www.ppgaerospace.com/getmedia/ba64914b-c114-46bb-8cc4-c2ab09d440ee/B737_TD_FINAL.pdf.aspx?ext=.pdf |title=Cockpit Windows Next-Generation 737, Classic 737, 727, 707 Airplanes |publisher=PPG Aerospace Transparencies |access-date=August 27, 2015 |archive-date=September 4, 2015 |archive-url=https://web.archive.org/web/20150904131052/http://www.ppgaerospace.com/getmedia/ba64914b-c114-46bb-8cc4-c2ab09d440ee/B737_TD_FINAL.pdf.aspx?ext=.pdf |url-status=live}} to allow for better crew visibility.{{cite web |title=Boeing Next-Generation 737 Gets a Face-Lift |url=http://boeing.mediaroom.com/2005-01-26-Boeing-Next-Generation-737-Gets-a-Face-Lift |website=Boeing Media Room |publisher=Boeing |access-date=March 25, 2018 |archive-date=March 26, 2018 |archive-url=https://web.archive.org/web/20180326064213/http://boeing.mediaroom.com/2005-01-26-Boeing-Next-Generation-737-Gets-a-Face-Lift |url-status=live}} Contrary to popular belief, these windows were not intended for celestial navigation{{cite web |last1=Wallace |first1=James |title=Aerospace Notebook: New Boeing 717 design is bound to lift quite a few eyebrows |url=https://www.seattlepi.com/business/article/Aerospace-Notebook-New-Boeing-717-design-is-1085849.php |website=seattlepi.com |date=April 24, 2002 |publisher=Hearst Seattle Media, LLC |access-date=March 25, 2018 |archive-date=July 3, 2018 |archive-url=https://web.archive.org/web/20180703075821/https://www.seattlepi.com/business/article/Aerospace-Notebook-New-Boeing-717-design-is-1085849.php |url-status=live}} (only the military T-43A had a sextant port for star navigation, which the civilian models lacked.){{sfn|Sharpe|Shaw|2001|p=[https://archive.org/details/boeing737100200a00mich/page/37 37]|ps=}} With modern avionics, the windows became redundant, and many pilots placed newspapers or other objects in them to block out sun glare. They were eliminated from the 737 cockpit design in 2004, although they are still installed on customer request.{{sfn|Brady|2014|pages=144–145}} The eyebrow windows were sometimes removed and plugged, usually during maintenance overhauls, and can be distinguished by the metal plug which differs from the smooth metal in later aircraft that were not originally fitted with the windows.{{sfn|Brady|2014|pages=144–145}}

The 737 was designed to sit relatively low to the ground to accommodate the design of smaller airports in the late 1960s which often lacked jetbridges or motorized belt loaders. The low fuselage allowed passengers to easily board from a mobile stairway or airstairs (which are still available as an option on the 737 MAX) and for luggage to be hand-lifted into the cargo holds. However, the design has proved to be an issue as the 737 has been modernized with larger and more fuel efficient engines.{{Cite web |last=Vartabedian |first=Ralph |date=March 15, 2019 |title=How a 50-year-old design came back to haunt Boeing with its troubled 737 Max jet |url=https://www.latimes.com/local/california/la-fi-boeing-max-design-20190315-story.html |access-date=February 5, 2024 |website=Los Angeles Times |language=en-US}}

The 737's main landing gear, under the wings at mid-cabin, rotates into wheel wells in the aircraft's belly. The legs are covered by partial doors, and "brush-like" seals aerodynamically smooth (or "fair") the wheels in the wells. The sides of the tires are exposed to the air in flight. "Hub caps" complete the aerodynamic profile of the wheels. It is forbidden to operate without the caps, because they are linked to the ground speed sensor that interfaces with the anti-skid brake system. The dark circles of the tires are clearly visible when a 737 takes off, or is at low altitude.Dekkers, Daniel, et al. (Project 2A2H). [home.deds.nl/~hink07/Report.pdf "Analysis Landing Gear 737-500."]{{dead link|date=November 2014}} Hogeschool van Amsterdam. Aviation Studies. October 2008. Retrieved: August 20, 2011.

From July 2008, the steel landing gear brakes on new NGs were replaced by Messier-Bugatti carbon brakes, achieving weight savings to {{Convert|550|–|700|lb}} depending on whether standard or high-capacity brakes were equipped.Volkmann, Kelsey. [http://www.bizjournals.com/stlouis/stories/2008/08/04/daily27.html "Boeing gets OK for new carbon brakes."] {{Webarchive|url=https://web.archive.org/web/20081008094401/http://www.bizjournals.com/stlouis/stories/2008/08/04/daily27.html |date=October 8, 2008}} St. Louis Business Journal via bizjournals.com. Retrieved: April 22, 2010. On a 737-800 this gives a 0.5% improvement in fuel efficiency.Wilhelm, Steve. [http://www.bizjournals.com/seattle/stories/2008/08/11/story13.html "Mindful of rivals, Boeing keeps tinkering with its 737."] {{Webarchive|url=https://web.archive.org/web/20121026075536/http://www.bizjournals.com/seattle/stories/2008/08/11/story13.html |date=October 26, 2012}} Puget Sound Business Journal, August 8, 2008. Retrieved: January 21, 2011.

737s are not equipped with fuel dump systems. The original design was too small to require this, and adding a fuel dump system to the later, larger variants would have incurred a large weight penalty. Boeing instead demonstrated an "equivalent level of safety". Depending on the nature of the emergency, 737s either circle to burn off fuel or land overweight. If the latter is the case, the aircraft must be inspected by maintenance personnel for damage before being returned to service.{{cite web|title=Boeing Commercial Aircraft – In-Flight Fuel Jettison Capability |url=http://www.boeing.com/assets/pdf/commercial/airports/faqs/fueldump.pdf |publisher=Boeing |access-date=November 23, 2014 |archive-date=March 10, 2015 |archive-url= https://web.archive.org/web/20150310192604/http://www.boeing.com/assets/pdf/commercial/airports/faqs/fueldump.pdf|url-status=live}}Cheung, Humphrey. [http://www.tgdaily.com/trendwatch-features/39149-troubled-american-airlines-jet-lands-safely-at-lax "Troubled American Airlines jet lands safely at LAX."] {{Webarchive|url=https://web.archive.org/web/20120606152043/http://www.tgdaily.com/trendwatch-features/39149-troubled-american-airlines-jet-lands-safely-at-lax |date=June 6, 2012}} tgdaily.com, September 2, 2008. Retrieved: August 20, 2011.

File:Boeing 737-200 planform view.jpg|Original 737 with JT8D engines that span the entire wing chord

File:Transaero b737-400 planform ei-cxk arp.jpg|737 Classic with larger CFM56 engines mounted mostly ahead of the wing

File:American Boeing 737-800 N886NN planform.jpg|alt=The 737NG with improved CFM56-7 engines and redesigned larger wing|737 Next Generation with improved CFM56-7 engines and redesigned wing

File:United Boeing 737-8 MAX N17322 planform.jpg|737 MAX with larger CFM LEAP engines, mounted even further ahead of the wing

Engines on the 737 Classic series (-300, -400, -500) and Next-Generation series (-600, -700, -800, -900) do not have circular inlets like most aircraft but rather a planform on the lower side, which has been dictated largely by the need to accommodate ever larger engine diameters. The 737 Classic series featured CFM56 high bypass turbofan engines, which were 25% more efficient and also reduced noise significantly over JT8D low bypass engines used on the 737 Original series (-100 and -200), but also posed an engineering challenge given the low ground clearance of the Boeing 737 family. Boeing and engine supplier CFM International (CFMI) solved the problem by placing the engine ahead of (rather than below) the wing, and by moving engine accessories to the sides (rather than the bottom) of the engine pod, giving the 737 Classic and later generations a distinctive non-circular air intake.{{sfn|Endres|2001|p=128|ps=}}

The improved, higher pressure ratio CFM56-7 turbofan engine on the 737 Next Generation is 7% more fuel-efficient than the previous CFM56-3 on the 737 Classic with the same bypass ratio. The newest 737 variants, the 737 MAX series, feature LEAP-1B engines from CFMI with a {{Convert|1.76|m|in|order=flip}} fan diameter. These engines were expected to be 10-12% more efficient than the CFM56-7B engines on the 737 Next Generation series.{{cite news |last= Ostrower |first= Jon |url= http://www.flightglobal.com/articles/2011/08/30/361428/boeing-designates-737-max-family.html |archive-url= https://web.archive.org/web/20110925210731/http://www.flightglobal.com/articles/2011/08/30/361428/boeing-designates-737-max-family.html |archive-date= September 25, 2011 |title= Boeing designates 737 MAX family |date= August 30, 2011 |work=Air Transport Intelligence |access-date =September 5, 2011}}

File:Boeing 737-200 (Brasilia Air Base) JT8D.jpg|Original 737 with JT8D engine mounted under the wing with original cowling design

File:Boeing 737-524.jpg|737 Classic with larger CFM56 engine mounted mostly ahead of the wing with an ovoid "hamster pouch" inlet with a flattened bottom

File:CFM-56 Lauda 737.jpg|737 Next Generation with CFM56-7 engine with a more rounded inlet due to a redesigned fan in the engine

File:Boeing 737-9 MAX CFM LEAP-1B PAS.jpg|737 MAX with larger CFM LEAP engines, mounted even further ahead of the wing a nacelle with chevrons

The 737 uses a hydro-mechanical flight control system,{{Cite web|url=https://leehamnews.com/2019/08/09/bjorns-corner-fly-by-steel-or-electrical-wire-part-3/|title=Bjorn's Corner: Fly by steel or electrical wire, Part 3|last=leehamcoeu|date=August 9, 2019|website=Leeham News and Analysis|language=en-US|access-date=January 10, 2020|archive-date=July 27, 2020|archive-url=https://web.archive.org/web/20200727020948/https://leehamnews.com/2019/08/09/bjorns-corner-fly-by-steel-or-electrical-wire-part-3/|url-status=live}} similar to the Boeing 707 and typical of the period in which the 737 was originally designed. Pilot commands are transmitted to hydraulic boosters attached to the control surfaces via steel cables that run through the fuselage and wings, rather than by the electrical fly-by-wire systems found in more recent designs like the Airbus A320 or Boeing 777.

The primary flight controls have mechanical backups. In the event of total hydraulic system failure or double engine failure, they will automatically revert to control via servo tab. In this mode, termed manual reversion, the servo tabs aerodynamically control the elevators and ailerons; these servo tabs are in turn controlled by cables running to the control yoke. The pilot's muscle forces alone control the tabs.

The 737 Next Generation series introduced a six-screen LCD glass cockpit with modern avionics but designed to retain crew commonality with previous 737 generations.{{cite web |url=http://theflyingengineer.com/flightdeck/boeings-max-southwests-737/ |title=Boeing's MAX, Southwest's 737 |publisher=theflyingengineer |access-date=August 27, 2015 |date=December 13, 2011 |archive-date=September 7, 2015 |archive-url=https://web.archive.org/web/20150907035228/http://theflyingengineer.com/flightdeck/boeings-max-southwests-737/ |url-status=live}}

The 737 MAX introduced a 4 15.1 inch landscape LCD screen cockpit manufactured by Rockwell Collins derived from the Boeing 787 Dreamliner. Except for the spoilers, which are fly-by-wire controlled, and all the analog instruments, which became digital, everything else is similar to the cockpits of the previous 737 generations to maintain commonality.{{citation needed|date=June 2021}}

File:Boeing 737-2V6 Advanced Cockpit Dubai Air Show Ryabtsev.jpg|Original 737 cockpit

File:Cockpit of 737-300 LN-KKU.jpg|737 Classic cockpit

File:S7 Airlines Boeing 737-8ZS flight deck Beltyukov.jpg|737 Next Generation cockpit

File:737 Max Cockpit.jpg|737 MAX cockpit

The Original -100 and -200 series were built without wingtip devices, but these were later introduced to improve fuel efficiency. The 737 has evolved four winglet types: the 737-200 Mini-winglet, 737 Classic/NG Blended Winglet, 737 Split Scimitar Winglet, and 737 MAX Advanced Technology Winglet.{{sfn|Brady|2014|pages=144–145}} The 737-200 Mini-winglets are part of the Quiet Wing Corp modification kit that received certification in 2005.{{sfn|Brady|2014|pages=144–145}}

Blended winglets were standard on the 737 NG since 2000 and are available for retrofit on 737 Classic models. These winglets stand approximately {{Convert|8|ft|m}} tall and are installed at the wing tips. They improve fuel efficiency by up to 5% through lift-induced drag reduction achieved by moderating wingtip vortices.{{cite web |url=http://www.boeing.com/commercial/aeromagazine/articles/qtr_03_09/pdfs/AERO_Q309_article03.pdf |title=Blended winglets improve performance |work=Aero Magazine |year=2009 |access-date=July 27, 2011 |last=Freitag |first=William |author2=Schulze, Terry |pages=9, 12 |archive-date=June 29, 2011 |archive-url=https://web.archive.org/web/20110629121337/http://www.boeing.com/commercial/aeromagazine/articles/qtr_03_09/pdfs/AERO_Q309_article03.pdf |url-status=live}}{{cite web |url=http://www.boeing.com/commercial/aeromagazine/aero_17/winglet_story.html |title=Blended Winglets |last1=Faye |first1=Robert |year=2002 |last2=Laprete |first2=Robert |last3=Winter |first3=Michael |work=Aero Magazine |access-date=July 27, 2011 |archive-date=June 29, 2011 |archive-url=https://web.archive.org/web/20110629044709/http://www.boeing.com/commercial/aeromagazine/aero_17/winglet_story.html |url-status=live}}

Split Scimitar winglets became available in 2014 for the 737-800, 737-900ER, BBJ2 and BBJ3, and in 2015 for the 737-700, 737-900 and BBJ1.{{cite web |title = Split Scimitar Schedules |url = http://www.aviationpartnersboeing.com/products_splitscimitar_schedules.php |website = aviationpartnersboeing.com |access-date = May 29, 2015 |archive-date = May 20, 2015 |archive-url = https://web.archive.org/web/20150520160554/http://www.aviationpartnersboeing.com/products_splitscimitar_schedules.php |url-status = live}} Split Scimitar winglets were developed by Aviation Partners, the same Seattle-based corporation that developed the blended winglets; the Split Scimitar winglets produce up to a 5.5% fuel savings per aircraft compared to 3.3% savings for the blended winglets. Southwest Airlines flew their first flight of a 737-800 with Split Scimitar winglets on April 14, 2014.{{cite web |title = Southwest flies first 737 with new 'split scimitar' winglets |website = USA Today |url = https://www.usatoday.com/story/todayinthesky/2014/04/10/southwest-flies-first-737-with-new-split-scimitar-winglets/7552849/ |access-date = May 29, 2015 |archive-date = March 15, 2015 |archive-url = https://web.archive.org/web/20150315171924/http://www.usatoday.com/story/todayinthesky/2014/04/10/southwest-flies-first-737-with-new-split-scimitar-winglets/7552849/ |url-status = live}} The next generation 737, 737 MAX, will feature an Advanced Technology (AT) Winglet that is produced by Boeing. The Boeing AT Winglet resembles a cross between the Blended Winglet and the Split Scimitar Winglet.{{cite web |url=https://mme.fiu.edu/wp-content/uploads/2013/12/F13-OR-T-10.pdf |title=Design, Analysis and Multi-Objective Constrained Optimization of Multi-Winglets |publisher=Florida International University |access-date=August 27, 2015 |archive-date=September 4, 2015 |archive-url=https://web.archive.org/web/20150904131054/https://mme.fiu.edu/wp-content/uploads/2013/12/F13-OR-T-10.pdf |url-status=live}}

An optional Enhanced Short Runway Package was developed for use on short runways.

File:2011-05-19-flughafen-erfurt-by-RalfR-43 737 Air Berlin.jpg|Blended Winglet, standard on 737 Next Generation, a retrofit option for Classics

File:B737-800 Split Winglet WP 20141110 001.jpg|Split Scimitar Winglet standard on later 737 Next Generation models

File:Boeing 737 MAX (23326959580) winglet.jpg|Advanced Technology Winglet standard on MAX

The first generation Original series 737 cabin was replaced for the second generation Classic series with a design based on the Boeing 757 cabin. The Classic cabin was then redesigned once more for the third, Next Generation, 737 with a design based on the Boeing 777 cabin. Boeing later offered the redesigned Sky Interior on the NG. The principal features of the Sky Interior include sculpted sidewalls, redesigned window housings, increased headroom and LED mood lighting,Kingsley-Jones, Max. [https://web.archive.org/web/20091031114910/http://www.flightglobal.com/articles/2009/10/27/333973/narrow-margins-airbus-and-boeing-face-pressure-with-the-a320-and-737.html "Narrow margins: Airbus and Boeing face pressure with the A-320 and 737."] flightglobal.com, October 27, 2009. Retrieved: June 23, 2010.[http://www.businessinsider.com/check-out-boeings-swanky-new-high-tech-interior-2011-1 "Check Out Boeing's Swanky New High-Tech Interior."] {{Webarchive|url=https://web.archive.org/web/20110116060047/http://www.businessinsider.com/check-out-boeings-swanky-new-high-tech-interior-2011-1 |date=January 16, 2011}} businessinsider.com. Retrieved: November 1, 2011. larger pivot-bins based on the 777 and 787 designs and generally more luggage space, and claims to have improved cabin noise levels by 2–4 dB. The first 737 equipped Boeing Sky Interior was delivered to Flydubai in late 2010. Continental Airlines,{{cite web|title=Continental first North American carrier to offer Boeing's new Sky Interior|url=http://www.flightglobal.com/news/articles/continental-first-north-american-carrier-to-offer-boeings-new-sky-351392/|publisher=Flightglobal|access-date=November 22, 2014|date=December 29, 2010|archive-date=November 29, 2014|archive-url=https://web.archive.org/web/20141129045515/http://www.flightglobal.com/news/articles/continental-first-north-american-carrier-to-offer-boeings-new-sky-351392/|url-status=live}}{{cite web|title=Continental Airlines Is First North American Carrier to Fly With Boeing's New Sky Interior |url=http://ir.unitedcontinentalholdings.com/phoenix.zhtml?c=83680&p=irol-newsArticle&ID=1511190 |archive-url=https://archive.today/20141122182710/http://ir.unitedcontinentalholdings.com/phoenix.zhtml?c=83680&p=irol-newsArticle&ID=1511190 |url-status=dead |archive-date=November 22, 2014 |website=ir.unitedcontinentalholdings.com |publisher=United Airlines |access-date=November 22, 2014 |date=December 29, 2010}} Alaska Airlines,{{Cite news|url=https://www.alaskaair.com/content/travel-info/our-aircraft/737-800|title=Boeing 737-800 Aircraft Information |last=|first=|work=Alaska Airlines|access-date=June 21, 2018|language=en|archive-date=May 27, 2021|archive-url=https://web.archive.org/web/20210527120655/https://www.alaskaair.com/content/travel-info/our-aircraft/737-800|url-status=live}} Malaysia Airlines,{{cite web |url=http://www.flightglobal.com/news/articles/pictures-mas-takes-delivery-of-first-737-800-with-sky-interior-349155/ |title=MAS takes delivery of first 737-800 with Sky Interior |publisher=Flightglobal.com |date=November 1, 2010 |access-date=April 29, 2013 |archive-date=May 15, 2013 |archive-url=https://web.archive.org/web/20130515123103/http://www.flightglobal.com/news/articles/pictures-mas-takes-delivery-of-first-737-800-with-sky-interior-349155/ |url-status=live}} and TUIFly have also received Sky Interior-equipped 737s.[http://www.podcastexperten.de/news/07032011-wolkenlos-seattle-produktion-den-usa-f%C3%BCr-tuifly.html "Wolkenlos in Seattle – an Bord des neuen Jets von TUIfly."] {{Webarchive|url=https://web.archive.org/web/20110901072351/http://www.podcastexperten.de/news/07032011-wolkenlos-seattle-produktion-den-usa-f%C3%BCr-tuifly.html |date=September 1, 2011}} podcastexperten, March 7, 2011. Retrieved: May 12, 2011.

File:Lufthansa 737 interior.jpg|737 Classic interior

File:Delta Air Lines Boeing 737-800 cabin.jpg|737 Next Generation standard interior

File:Norwegian Boeing 737-800 cabin Sky Interior.JPG|737 Next Generation Sky Interior with pivot bins and LED lighting

File:공중조기경보통제기 (7445565660).jpg is an Airborne Early Warning and Control version of the 737-700.]]

{{main|Boeing 737 AEW&C}}

The Boeing 737 AEW&C is a 737-700IGW roughly similar to the 737-700ER. This is an Airborne Early Warning and Control (AEW&C) version of the 737NG. Australia is the first customer (as Project Wedgetail), followed by Turkey and South Korea.{{citation needed|date=April 2022}}

{{main|Boeing T-43}}File:T-43 2.jpg was a 737-200 used by the United States Air Force to train navigators.]]The T-43 was a 737-200 modified for use by the United States Air Force for training navigators, now known as USAF combat systems officers. Informally referred to as the Gator (an abbreviation of "navigator") and "Flying Classroom", nineteen of these aircraft were delivered to the Air Training Command at Mather AFB, California during 1973 and 1974. Two additional aircraft were delivered to the Colorado Air National Guard at Buckley ANGB (later Buckley AFB) and Peterson AFB, Colorado, in direct support of cadet air navigation training at the nearby U.S. Air Force Academy.{{citation needed|date=April 2022}}

Two T-43s were later converted to CT-43As, similar to the CT-40A Clipper below, in the early 1990s and transferred to Air Mobility Command and United States Air Forces in Europe, respectively, as executive transports. A third aircraft was also transferred to Air Force Materiel Command for use as a radar test bed aircraft and was redesignated as an NT-43A. The T-43 was retired by the Air Education and Training Command in 2010 after 37 years of service.{{Cite web|title=Air Force bids farewell to T-43|url=http://www.airforcetimes.com/news/2010/09/air-force-t43-farewell-091710/|publisher=Army Times Publishing Company|author=Michelle Tan|access-date=January 10, 2020|archive-date=July 2, 2012|archive-url=https://archive.today/20120702221111/http://www.airforcetimes.com/news/2010/09/air-force-t43-farewell-091710/|url-status=live}}

File:US Navy 100126-N-0705K-003 Naval Air Crewmen 2nd Class Nicole Garza and David Murray and Naval Air Crewman 1st Class David McDermott load cargo bound for Haiti at Naval Air Station Jacksonville.jpg is a military version of the 737-700C.|219x219px]]

{{main|Boeing C-40 Clipper}}

The Boeing C-40 Clipper is a military version of the 737-700C NG. It is used by both the United States Navy and the United States Air Force, and has been ordered by the United States Marine Corps.{{Cite web |url = https://www.flightglobal.com/news/articles/us-marine-corps-looks-to-buy-two-c-40-executive-tran-454181/ |title = US Marine Corps looks to buy two C-40 executive transports |first = Garrett |last = Reim |date = December 5, 2018 |website = FlightGlobal |via = Flightglobal.com |access-date = May 29, 2019 |archive-url = https://web.archive.org/web/20190425091848/https://www.flightglobal.com/news/articles/us-marine-corps-looks-to-buy-two-c-40-executive-tran-454181/ |archive-date = April 25, 2019 |url-status = live}} Technically, only the Navy C-40A variant is named "Clipper", whereas the USAF C-40B/C variants are officially unnamed.

{{main|Boeing P-8 Poseidon}}

File:US Navy P-8 Poseidon taking off at Perth Airport.jpg is a 737-800 variant for anti-submarine warfare, anti-surface warfare, and shipping interdiction.|219x219px]]

The P-8 Poseidon developed for the United States Navy by Boeing Defense, Space & Security, based on the Next Generation 737-800ERX. The P-8 can be operated in the anti-submarine warfare (ASW), anti-surface warfare (ASUW), and shipping interdiction roles. It is armed with torpedoes, Harpoon anti-ship missiles and other weapons, and is able to drop and monitor sonobuoys, as well as operate in conjunction with other assets such as the Northrop Grumman MQ-4C Triton maritime surveillance unmanned aerial vehicle (UAV).

The VC-96 designation was applied to two 737-2N3s operated by the Brazilian Air Force's Special Transport Group (GTE).{{Cite web |title=Brazilian Military Aircraft Designations |url=https://designation-systems.net/non-us/brazil.html |access-date=2025-03-17 |website=designation-systems.net}}{{Cite web |date=2023-03-22 |title=Grupo de Transporte Especial – História da Força Aérea Brasileira |url=https://historiadafab.rudnei.cunha.nom.br/2021/01/06/grupo-de-transporte-especial/ |access-date=2025-03-17 |language=pt-BR}}

{{main|Boeing Business Jet}}

File:Boeing 737-75V BBJ AN1425895.jpg

In the late 1980s, Boeing marketed the 77-33 jet, a business jet version of the 737-300.Endres 2001. The name was short-lived. After the introduction of the Next Generation series, Boeing introduced the Boeing Business Jet (BBJ) series. The BBJ1 was similar in dimensions to the 737-700 but had additional features, including stronger wings and landing gear from the 737-800, and had increased range over the other 737 models through the use of extra fuel tanks. The first BBJ rolled out on August 11, 1998, and flew for the first time on September 4.{{Citation needed|date=August 2024}}

On October 11, 1999, Boeing launched the BBJ2. Based on the 737-800, it is {{Convert|5.84|m|ftin|sp=us|order=flip}} longer than the BBJ1, with 25% more cabin space and twice the baggage space, but has slightly reduced range. It is also fitted with auxiliary belly fuel tanks and winglets. The first BBJ2 was delivered on February 28, 2001.{{Citation needed|date=August 2024}}

Boeing's BBJ3 is based on the 737-900ER. The BBJ3 has {{Convert|1120|sqft|m2}} of floor space, 35% more interior space, and 89% more luggage space than the BBJ2. It has an auxiliary fuel system, giving it a range of up to {{Convert|4725|nmi}}, and a Head-up display. Boeing completed the first example in August 2008. This aircraft's cabin is pressurized to a simulated {{Convert|6500|ft|m|adj=on}} altitude.{{cite web|title=Boeing Business Jets Launches New Family Member|url=http://boeing.mediaroom.com/2006-10-16-Boeing-Business-Jets-Launches-New-Family-Member|publisher=Boeing|access-date=November 22, 2014|date=October 16, 2006|archive-date=November 29, 2014|archive-url=https://web.archive.org/web/20141129065426/http://boeing.mediaroom.com/2006-10-16-Boeing-Business-Jets-Launches-New-Family-Member|url-status=live}}{{cite web|title=Boeing Completes First BBJ 3|url=https://www.wingsmagazine.com/news/boeing-completes-first-bbj-3-1833|website=www.wingsmagazine.com|publisher=Wings|access-date=November 22, 2014|date=August 14, 2008|archive-date=December 14, 2014|archive-url=https://web.archive.org/web/20141214023900/https://www.wingsmagazine.com/news/boeing-completes-first-bbj-3-1833|url-status=live}}

The Boeing Converted Freighter program (BCF), or the 737-800BCF program, was launched by Boeing in 2016. It converts old 737-800 passenger jets to dedicated freighters.{{Cite news|url=https://www.flightglobal.com/news/articles/boeing-launches-737-800bcf-programme-422323/|title=Boeing launches 737-800BCF programme|date=February 24, 2016|work=Flightglobal.com|access-date=April 30, 2018|language=en-GB|archive-date=July 25, 2018|archive-url=https://web.archive.org/web/20180725184044/https://www.flightglobal.com/news/articles/boeing-launches-737-800bcf-programme-422323/|url-status=live}} The first 737-800BCF was delivered in 2018 to GECAS, which is leased to West Atlantic.{{Cite news|url=https://www.flightglobal.com/news/articles/boeing-delivers-first-737-800bcf-to-west-atlantic-447850/|title=Boeing delivers first 737-800BCF to West Atlantic|date=April 20, 2018|work=Flightglobal.com|access-date=April 30, 2018|language=en-GB|archive-date=April 30, 2018|archive-url=https://web.archive.org/web/20180430115208/https://www.flightglobal.com/news/articles/boeing-delivers-first-737-800bcf-to-west-atlantic-447850/|url-status=live}} Boeing has signed an agreement with Chinese YTO Cargo Airlines to provide the airline with 737-800BCFs pending a planned program launch.[http://www.aviationanalysis.net/2015/10/boeing-to-launch-737-freighter-conversion.html "Boeing to launch 737 freighter conversion program"] {{Webarchive|url=https://web.archive.org/web/20151003085815/http://www.aviationanalysis.net/2015/10/boeing-to-launch-737-freighter-conversion.html |date=October 3, 2015}}. aviationanalysis.net

{{main|ecoDemonstrator}}

Four 737 aircraft have been used in Boeing test programs. In 2012, a new 737-800 bound for American Airlines became the first ecoDemonstrator airframe in a program that continues annually into the 2020s. In conjunction with many industry partners, the program aims to reduce the environmental impact of aviation. In 2012 it tested the winglets which would eventually be used in the 737 MAX series.{{cite web |last1=Broadbent |first1=Mark |title=Commercial Boeing ecoDemonstrator |url=https://www.key.aero/article/triple-seven-testbed |website=Key.Aero |publisher=Key Publishing Ltd. |access-date=October 19, 2022 |date=June 27, 2019}} Testing also included a variable area exhaust nozzle, regenerative hydrogen fuel cells for electrical power, and sustainable aviation fuel (SAF).

In 2018, one of the 737 MAX 7 prototypes participated in Boeing's Quiet Technology Demonstrator 3 (QTD3) program, in which a NASA engine inlet designed to reduce engine noise was tested over an acoustic array at Moses Lake, Washington.{{cite web |last1=Womg |first1=Jackie W. |last2=Nesbitt |first2=Eric H. |last3=Jones |first3=Michael G. |last4=Nark |first4=Douglas M. |title=Flight Test Methodology for NASA Advanced Inlet Liner on 737MAX-7 Test Bed (Quiet Technology Demonstrator 3) |url=https://ntrs.nasa.gov/api/citations/20200002460/downloads/20200002460.pdf?attachment=true |website=2019 AIAA Aeroacoustics Conference |publisher=NASA |access-date=November 21, 2022 |date=May 20, 2019}}

A 737 MAX 9 was used as the 2021 ecoDemonstrator. A new airframe in a special Alaska Airlines livery flew an extensive test program, a major part of which was the use of SAF in blends of up to 50% including a flight from Seattle to Glasgow, Scotland, to attend the United Nations COP26 Climate Change Conference.{{cite web |last1=Robinson |first1=Tim |last2=Read |first2=Bill |title=Boeing charts a greener flight path |url=https://www.aerosociety.com/news/boeing-charts-a-greener-flight-path/ |website=RAeS |publisher=Royal Aeronautical Society |access-date=November 21, 2022 |date=October 26, 2021}} Other test areas included halon-free fire extinguisher (ground testing only), a low-profile anti-collision light, and text-based air traffic control communications.{{cite web |last1=Norris |first1=Guy |title=Boeing ecoDemonstrator Assumes Growing Role |url=https://aviationweek.com/special-topics/sustainability/boeing-ecodemonstrator-assumes-growing-role |website=Aviation Week |publisher=Informa Markets |access-date=January 11, 2024 |date=October 19, 2021}} At the end of the testing the aircraft was returned to standard configuration, and was delivered to Alaska Airlines in 2022.

During October 2023 a 737 MAX 10 destined for United Airlines flew a series of test flights to compare the emissions of SAF, including the contrails, with those of conventional fuel. The emissions were measured by NASA's Douglas DC-8 Airborne Science Lab which flew close behind the 737, which wore a special livery as part of a series of special tests named ecoDemonstrator Explorer.{{cite web |title=NASA, Partners Explore Sustainable Fuel's Effects on Aircraft Contrails |url=https://www.nasa.gov/centers-and-facilities/armstrong/nasa-partners-explore-sustainable-fuels-effects-on-aircraft-contrails/ |website=NASA |access-date=November 17, 2023 |date=November 14, 2023}}

{{main|Competition between Airbus and Boeing#Single_aisles:_A320_vs_737|label 1= Competition between Airbus A320 and Boeing 737}}

File:United Airlines Airbus A320 and Boeing 737-800 on final approach at San Francisco.jpg Airbus A320 (front) and Boeing 737-900 on final approach]]

File:737 vs a320 family deliveries per model 1967-2018.png

The Boeing 737 Classic, Next Generation and MAX series have faced significant competition from the Airbus A320 family first introduced in 1988. The relatively recent Airbus A220 family now also competes against the smaller capacity end of the 737 variants. The A320 was developed to compete also with the McDonnell Douglas MD-80/90 and 95 series; the 95 later becoming the Boeing 717. Since July 2017, Airbus had a 59.4% market share of the re-engined single aisle market, while Boeing had 40.6%; Boeing had doubts on over-ordered A320neos by new operators and expected to narrow the gap with replacements not already ordered.{{cite news |url= https://leehamnews.com/2016/09/22/boeing-positioned-narrow-market-share-gap/ |title= Boeing positioned to narrow market share gap |date= September 22, 2016 |work= Leeham Co. |access-date= January 10, 2020 |archive-date= July 27, 2020 |archive-url= https://web.archive.org/web/20200727040708/https://leehamnews.com/2016/09/22/boeing-positioned-narrow-market-share-gap/ |url-status= live}} However, in July 2017, Airbus had still 1,350 more A320neo orders than Boeing had for the 737 MAX.{{cite web |url= https://airinsight.com/big-duopoly-race/ |title= The Big Duopoly Race |date= July 10, 2017 |publisher= Airinsight |author= Addison Schonland |access-date= January 10, 2020 |archive-date= May 12, 2020 |archive-url= https://web.archive.org/web/20200512044542/https://airinsight.com/big-duopoly-race/ |url-status= live}}

Boeing delivered 8,918 of the 737 family between March 1988 and December 2018, while Airbus delivered 8,605 A320 family aircraft over a similar period since first delivery in early 1988.{{cite web|url=http://www.airbus.com/no_cache/company/market/orders-deliveries|title=Orders & deliveries viewer|publisher=Airbus|access-date=January 11, 2019|url-status=dead|archive-url=https://web.archive.org/web/20121230235718/http://www.airbus.com/no_cache/company/market/orders-deliveries/|archive-date=December 30, 2012}}

{{GraphChart|width=600|height=200|yGrid=

|type=line

|xAxisTitle=Year

|x=1988,1989,1990,1991,1992,1993,1994,1995,1996,1997,1998,1999,2000,2001,2002,2003,2004,2005,2006,2007,2008,2009,2010,2011,2012,2013,2014,2015,2016,2017,2018,2019,2020,2021,2022

|yAxisTitle=Deliveries

|y1Title=Airbus A320 family

|y1=16,58,58,119,111,71,64,56,72,127,168,222,241,257,236,233,233,289,339,367,386,402,401,421,455,493,490,491,545,558,626,642,446,483,516

|y2Title=Boeing 737 series

|y2=165,146,174,215,218,152,121,89,76,135,282,320,282,299,223,173,202,212,302,330,290,372,376,372,415,440,485,495,490,529,580,127,43,263,387

|colors=green,blue}}

• {{legend|green|Airbus A320 family deliveries{{cite web |url=http://www.airbus.com/fileadmin/media_gallery/files/reports_results_reviews/Summary_Historial_Orders_Deliveries_1974-2009.xls |archive-url=https://web.archive.org/web/20101223185526/http://www.airbus.com/fileadmin/media_gallery/files/reports_results_reviews/Summary_Historial_Orders_Deliveries_1974-2009.xls |archive-date=December 23, 2010 |title = Historical Orders and Deliveries 1974–2009 |work=Airbus S.A.S. |date=January 2010 |format=Microsoft Excel |access-date=December 10, 2012|url-status=live}}{{Cite web |url=https://www.airbus.com/aircraft/market/orders-deliveries.html |title=Airbus O&D |publisher=Airbus S.A.S. |date=December 31, 2020 |access-date= January 8, 2021}}}}
• {{legend|blue|Boeing 737 series deliveries{{cite web |url=http://active.boeing.com/commercial/orders/displaystandardreport.cfm?&optReportType=HistAnnDel |title= Historical Deliveries |publisher=Boeing |date= December 2015 |access-date=February 5, 2016|archive-url=https://web.archive.org/web/20200226093221/http://active.boeing.com/commercial/orders/displaystandardreport.cfm?&optReportType=HistAnnDel|archive-date=February 26, 2020|url-status=dead}}{{Cite web |url=http://www.boeing.com/company/about-bca/#/market |title=Boeing: About Boeing Commercial Airplanes |publisher=Boeing |date=December 31, 2020 |access-date= January 13, 2021}}}}

{{main|List of Boeing 737 operators}}

The five largest operators of the Boeing 737 are Southwest Airlines (815), Ryanair (566), United Airlines (496), American Airlines (363), and Delta Air Lines (240) as of June 2024.{{Citation needed|date=August 2024}}

File:N8616C Southwest Airlines 2013 Boeing 737-8H4 - cn 36914 - ln 4627 (12608580994).jpg.]]

In 2006, over 4,500 Boeing 737s were operated by more than 500 airlines, flying to 1,200 destinations in 190 countries and on average 1,250 aircraft were airborne, with two either departing or landing every five seconds.{{cite news |url= https://www.flightglobal.com/the-737-story-little-wonder/65316.article |title= The 737 Story: Little Wonder |work= flightglobal |date= February 7, 2006 |access-date= January 9, 2020 |archive-date= July 27, 2020 |archive-url= https://web.archive.org/web/20200727014549/https://www.flightglobal.com/the-737-story-little-wonder/65316.article |url-status= live}} The 737 was the most commonly flown aircraft in 2008,{{cite news |url= https://www.chicagotribune.com/2008/01/04/boeing-airliner-deliveries-rise-11/ |title= Boeing airliner deliveries rise 11% |work= Chicago Tribune |date= January 4, 2008 |quote= Boeing's 737, the world's most widely flown aircraft|url-status= live |archive-url= https://web.archive.org/web/20120315224042/http://articles.chicagotribune.com/2008-01-04/business/0801030652_1_airbus-sas-boeing-planemaker |archive-date= March 15, 2012}} 2009,{{cite news |author= O'Sullivan, Matt |url= http://www.smh.com.au/business/boeing-shelves-plans-for-737-replacement-20090101-78f5.html |title= Boeing shelves plans for 737 replacement |work= The Sydney Morning Herald |date= January 2, 2009 |quote= the 737, the world's most widely flown aircraft|archive-url= https://web.archive.org/web/20121106054059/http://www.smh.com.au/business/boeing-shelves-plans-for-737-replacement-20090101-78f5.html |archive-date= November 6, 2012}} and 2010.{{cite news |author= Layne, Rachel |url= http://www.businessweek.com/news/2010-02-26/bombardier-s-win-may-prod-airbus-boeing-to-upgrade-engines.html |title= Bombardier's Win May Prod Airbus, Boeing to Upgrade Engines |work= BusinessWeek |date= February 26, 2010 |quote= the 737, the world's most widely flown plane|archive-url= https://web.archive.org/web/20100301154738/http://www.businessweek.com/news/2010-02-26/bombardier-s-win-may-prod-airbus-boeing-to-upgrade-engines.html |archive-date= March 1, 2010}}

In 2013, over 5,580 Boeing 737s were operated by more than 342 airlines in 111 countries, which represented more than 25% of the worldwide fleet of large jet airliners. The 737 had carried over 16.8 billion passengers (twice of 7.1 billion world population in that time) over 119 billion miles (192 billion km) with more than 184 million flights or 264 million hours in the air.{{cite web |title=Boeing 737 Facts |url=https://www.boeing.com/farnborough2014/pdf/BCA/fct%20-737%20Family%20Facts.pdf |publisher=Boeing |date=December 31, 2013 |access-date=September 21, 2021 |url-status=live |archive-url=https://web.archive.org/web/20140722173233/http://www.boeing.com/farnborough2014/pdf/BCA/fct%20-737%20Family%20Facts.pdf |archive-date=July 22, 2014}}

In 2016, there were 6,512 Boeing 737 airliners in service (5,567 737NGs plus 945 737-200s and 737 Classics), more than the 6,510 Airbus A320 family.{{cite news |url= https://www.flightglobal.com/analysis-flightglobal-airliner-census-reveals-fleet-developments/121373.article |title= FlightGlobal airliner census reveals fleet developments |author= Dan Thisdell |date= August 8, 2016 |access-date= March 16, 2020 |archive-date= July 26, 2020 |archive-url= https://web.archive.org/web/20200726202339/https://www.flightglobal.com/analysis-flightglobal-airliner-census-reveals-fleet-developments/121373.article |url-status= live}} while in 2017, there were 6,858 737s in service (5,968 737NGs plus 890 737-200s and classics), fewer than the 6,965 A320 family.{{cite news |url= https://www.flightglobal.com/asset/18365 |archive-url= https://web.archive.org/web/20190827101030/https://www.flightglobal.com/asset/18365 |url-status= dead |archive-date= August 27, 2019 |title= 787 stars in annual airliner census |author= Dan Thisdell |date= August 14, 2017}}{{Verify source|date=March 2020}}

By 2018, over 7,500 Boeing 737s were in service and on average 2,800 aircraft were airborne, with two either departing or landing every three seconds, carrying around three million passengers daily. At the time, the global 737 fleet had carried over 22 billion passengers since its introduction.{{cite news |url= https://www.bizjournals.com/seattle/news/2018/03/13/boeing-renton-737-10000-southwest-guinness-record.html |title= Boeing Renton pushes 10,000th 737 jet out of factory and sets Guinness World Record (Photos) |work= bizjournals |date= March 13, 2018 |access-date= January 12, 2023}}

{{as of|2021|6}}, there were 9,315 Boeing 737s in service,{{cite news |url= https://www.reuters.com/business/aerospace-defense/faa-orders-checks-9300-boeing-737-planes-possible-switch-failures-2021-07-15/ |title= FAA orders checks on 9,300 Boeing 737 planes for possible switch failures |work= Reuters |date= July 15, 2021 |access-date= August 8, 2021}} slightly fewer than the 9,353 of the A320 family,{{Cite web |url=https://www.airbus.com/aircraft/market/orders-deliveries.html |title=Airbus Orders and Deliveries |date=June 30, 2021 |access-date=August 8, 2021 |url-status=live |work=Airbus |format=XLS |archive-url=https://web.archive.org/web/20171218195733/http://www.airbus.com/aircraft/market/orders-deliveries.html |archive-date=December 18, 2017}} as more 737s were already out of service.

File:TNI-AU Boeing 737-200 Lim.jpg Boeing 737-2X9 Surveiller (AI-7302) at Sultan Abdul Aziz Shah Airport]]

Many countries operate the 737 passenger, BBJ, and cargo variants in government or military applications.{{cite web |url=http://www.seattlepi.com/business/article/Boeing-looks-to-sell-more-737-based-military-jets-1417659.php |title=Boeing looks to sell more 737-based military jets |publisher=SeattlePi |date=June 9, 2011 |access-date=August 27, 2015 |archive-date=August 24, 2015 |archive-url=https://web.archive.org/web/20150824082917/http://www.seattlepi.com/business/article/Boeing-looks-to-sell-more-737-based-military-jets-1417659.php |url-status=live}} Users with 737s include:

{{div col|colwidth=11em}}

• {{ARG}}
• {{AUS}}
• {{BRA}}
• {{CHI}}
• {{CHN}}
• {{COL}}
• {{DRC}}
• {{IND}}
• {{IDN}}
• {{IRN}}
• {{KAZ}}
• {{MAS}}
• {{MEX}}
• {{MNG}}
• {{NED}}
• {{NGR}}
• {{PAK}}
• {{PER}}
• {{POL}}
• {{RSA}}
• {{KSA}}
• {{ROK}}
• {{TWN}}
• {{THA}}
• {{TUR}}
• {{GBR}}
• {{USA}}

{{div col end}}

The 737 had the highest, cumulative orders for any airliner until surpassed by the A320 family in October 2019.{{Cite news |url= https://www.flightglobal.com/news/articles/total-a320-orders-overtake-737s-as-max-crisis-persi-462255/ |title= A320's order total overtakes 737's as Max crisis persists |date= November 15, 2019 |author= David Kaminski-Morrow |work= Flightglobal |access-date= November 16, 2019 |archive-date= November 16, 2019 |archive-url= https://web.archive.org/web/20191116075424/https://www.flightglobal.com/news/articles/total-a320-orders-overtake-737s-as-max-crisis-persi-462255/ |url-status= live}} In that year, 737 orders dropped by 90%, as 737 MAX orders dried up after the March grounding.{{cite web |last1=Hawkins |first1=Andrew J. |title=Boeing had more cancellations than orders in 2019 as 737 Max crisis deepens |url=https://www.theverge.com/2020/1/14/21065581/boeing-orders-cancellation-737-max-2019 |website=The Verge |date=January 14, 2020 |access-date=January 25, 2020 |archive-date=January 25, 2020 |archive-url=https://web.archive.org/web/20200125051322/https://www.theverge.com/2020/1/14/21065581/boeing-orders-cancellation-737-max-2019 |url-status=live}} The 737 MAX backlog fell by 182, mainly due to the Jet Airways bankruptcy, a drop in Boeing's airliner backlog was a first in at least the past 30 years.{{cite news |last1=LeBeau |first1=Phil |title=Boeing posts negative commercial airplane orders in 2019 for first time in decades |url=https://www.cnbc.com/2020/01/14/boeing-posts-negative-commercial-airplane-orders-for-first-time-in-decades.html |work=CNBC |date=January 14, 2020 |access-date=January 25, 2020 |archive-date=January 25, 2020 |archive-url=https://web.archive.org/web/20200125031818/https://www.cnbc.com/2020/01/14/boeing-posts-negative-commercial-airplane-orders-for-first-time-in-decades.html |url-status=live}}

{{as of|2025|3|df=US}}, 16,805 units of the Boeing 737 family had been ordered, with 4,775 orders were pending, or 4,277 when including "additional criteria for recognizing contracted backlog with customers beyond the existence of a firm contract" (ASC 606 Adjustment).

File:737-deliveries-per-year-1967-2018.png

Boeing delivered the 5,000th 737 to Southwest Airlines on February 13, 2006, the 6,000th 737 to Norwegian Air Shuttle in April 2009,{{cite news |author= Kingsley-Jones, Max |url= https://www.flightglobal.com/pictures-6000-and-counting-for-boeings-popular-little-twinjet/86059.article |title= 6,000 and counting for Boeing's popular little twinjet |work= Flight International |date= April 22, 2009 |access-date= January 9, 2020 |archive-date= July 27, 2020 |archive-url= https://web.archive.org/web/20200727014427/https://www.flightglobal.com/pictures-6000-and-counting-for-boeings-popular-little-twinjet/86059.article |url-status= live}} the 7,000th 737 to Flydubai on December 16, 2011, the 8,000th 737 to United Airlines on April 16, 2014,{{cite news|title=Boeing's 737 Turns 8,000: The Best-Selling Plane Ever Isn't Slowing|url=http://www.businessweek.com/articles/2014-04-16/boeing-s-737-turns-8-000-the-best-selling-plane-ever-isn-t-slowing|publisher=Bloomberg Business Week|date=April 16, 2014|access-date=April 16, 2014|archive-date=April 16, 2014|archive-url=https://web.archive.org/web/20140416231815/http://www.businessweek.com/articles/2014-04-16/boeing-s-737-turns-8-000-the-best-selling-plane-ever-isn-t-slowing|url-status=dead}} and the 9,000th 737 to China United Airlines in April 2016.{{cite news |url= https://theworldofaviationblog.wordpress.com/2016/04/21/boeing-delivers-9000th-737/ |title= Boeing delivers 9,000th 737 |work= The World of Aviation |date= April 21, 2016 |access-date= October 13, 2021}} The 10,000th 737 was ordered in July 2012,{{cite news |url= http://www.boeing.com/Features/2012/07/bca_737_10000th_07_11_12.html |title= 737 tops 10,000 orders |publisher= Boeing |date= July 12, 2012|archive-url= https://web.archive.org/web/20120726002847/http://www.boeing.com/Features/2012/07/bca_737_10000th_07_11_12.html |archive-date= July 26, 2012}} rolled out on March 13, 2018, and was to be delivered to Southwest Airlines; the backlog at the time stood at over 4,600 aircraft.{{cite news |url= https://www.flightglobal.com/news/articles/analysis-how-boeing-built-10000-737s-446735/ |title= How Boeing built 10,000 737s |date= March 13, 2018 |author= Max Kingsley-Jones |work= Flightglobal |access-date= March 15, 2018 |archive-date= March 15, 2018 |archive-url= https://web.archive.org/web/20180315135255/https://www.flightglobal.com/news/articles/analysis-how-boeing-built-10000-737s-446735/ |url-status= live}}

{{as of|2025|3|df=US}}, 12,030 units of the Boeing 737 family had been delivered, while 11,971 of the competing A320 family had been delivered.{{cite web |title=Orders & Deliveries |url=https://www.airbus.com/aircraft/market/orders-deliveries.html |work=Airbus |date=March 31, 2025 |access-date=April 9, 2025 |url-status=live |archive-url=https://web.archive.org/web/20171218195733/http://www.airbus.com/aircraft/market/orders-deliveries.html |archive-date=December 18, 2017}}

Therefore, the 737 is the most delivered jetliner.{{cite news |url= https://www.nytimes.com/1998/05/11/us/faa-grounds-scores-of-737-s-to-check-for-a-wiring-problem.html |title= F.A.A. Grounds Scores of 737's To Check for a Wiring Problem |date= May 11, 1998 |work= New York Times}}{{cite news |url= https://aviationweek.com/air-transport/pilot-report-flying-737-8-boeings-new-narrowbody-breadwinner |title= Pilot Report: Flying the 737-8, Boeing's New Narrowbody Breadwinner |date= May 12, 2017 |work= Aviation Week}}{{cite news |author= O'Hare, Maureen |url= https://www.cnn.com/travel/article/world-best-selling-airplanes/index.html |title= The world's best-selling airplanes |date= January 28, 2022 |work= CNN}}

{{Notelist}}

{{clear}}

{{main|List of accidents and incidents involving the Boeing 737}}

{{Update section|date=June 2024|reason=Last updated in November 2023}}

{{as of|2023|11||df=US}}, the Boeing 737 family has been involved in 529 aviation accidents and incidents,[http://aviation-safety.net/database/dblist.php?Type=103 "Boeing 737 incident occurrences"] {{Webarchive|url=https://web.archive.org/web/20121026003108/http://aviation-safety.net/database/dblist.php?Type=103|date=October 26, 2012}}. Aviation-Safety.net, November 30, 2023. Retrieved: December 14, 2023. including 215 hull loss accidents out of 234 hull-losses, resulting in a total of 5,779 fatalities.[http://aviation-safety.net/database/type/type.php?type=103 "Boeing 737 Accident summary"] {{Webarchive|url=https://web.archive.org/web/20110804011602/http://aviation-safety.net/database/type/type.php?type=103|date=August 4, 2011}}. Aviation-Safety.net, November 30, 2023.. Retrieved: December 14, 2023.[http://aviation-safety.net/database/type/type-stat.php?type=103 "Boeing 737 Accident Statistics"] {{Webarchive|url=https://web.archive.org/web/20120323211704/http://aviation-safety.net/database/type/type-stat.php?type=103|date=March 23, 2012}}. Aviation-Safety.net, November 30, 2023.. Retrieved: December 14, 2023

A Boeing analysis of commercial jet airplane accidents between 1959 and 2013 found that the hull loss rate for the Original series was 1.75 per million departures, for the Classic series 0.54, and the Next Generation series 0.27.{{cite web|title=Statistical Summary of Commercial Jet Airplane Accidents – Accident Rates by Airplane Type|url=http://www.boeing.com/news/techissues/pdf/statsum.pdf|website=boeing.com|publisher=Boeing|page=19|date=August 2014|access-date=November 19, 2014|archive-date=November 1, 2014|archive-url=https://web.archive.org/web/20141101005316/http://www.boeing.com/news/techissues/pdf/statsum.pdf|url-status=live}} As of 2023, the analysis showed that the hull loss rate for the Original series was 1.78 (0.87 fatal hull loss rate), for the Classic series 0.81 (0.26 fatal hull loss rate), for the Next Generation series 0.18 (0.04 fatal hull loss rate), and for the MAX series 1.48 (1.48 fatal hull loss rate) per million departures.{{cite web |date=September 2023 |title=Statistical Summary of Commercial Jet Airplane Accidents |url=http://www.boeing.com/news/techissues/pdf/statsum.pdf |url-status=live |archive-url=https://web.archive.org/web/20141101005316/http://www.boeing.com/news/techissues/pdf/statsum.pdf |archive-date=1 November 2014 |access-date=30 June 2024 |publisher=Boeing |page=10}}

During the 1990s, a series of rudder issues on series -200 and -300 aircraft resulted in multiple incidents. In two total loss accidents, United Airlines Flight 585 (a -200 series) and USAir Flight 427, (a -300), the pilots lost control of the aircraft following a sudden and unexpected deflection of the rudder, killing everyone aboard, a total of 157 people.{{Cite news|url=https://news.google.com/newspapers?nid=1842&dat=19990912&id=LIUfAAAAIBAJ&sjid=bckEAAAAIBAJ&pg=3456,2004004|title=Report says Boeing 737 rudder problems linger|date=September 12, 1999|newspaper=TimesDaily|access-date=July 10, 2016|archive-date=October 7, 2018|archive-url=https://web.archive.org/web/20181007121023/https://news.google.com/newspapers?nid=1842&dat=19990912&id=LIUfAAAAIBAJ&sjid=bckEAAAAIBAJ&pg=3456,2004004|url-status=live}} Similar rudder issues led to a temporary loss of control on at least five other 737 flights before the problem was ultimately identified. The National Transportation Safety Board determined that the accidents and incidents were the result of a design flaw that could result in an uncommanded movement of the aircraft's rudder.{{cite book |url=https://www.ntsb.gov/investigations/AccidentReports/Reports/AAR0101.pdf |title=Uncontrolled Descent and Collision With Terrain, United Airlines Flight 585, Boeing 737-200, N999UA, 4 Miles South of Colorado Springs Municipal Airport, Colorado Springs, Colorado, March 3, 1991 |publisher=National Transportation Safety Board |id=NTSB/AAR-01-01 |date=March 27, 2001 |access-date=January 17, 2016 |archive-date=October 2, 2015 |archive-url=https://web.archive.org/web/20151002041524/http://www.ntsb.gov/investigations/AccidentReports/Reports/AAR0101.pdf |url-status=live}}{{rp|13}}{{cite book |date=March 24, 1999 |publisher=National Transportation Safety Board |url=https://www.ntsb.gov/investigations/AccidentReports/Reports/AAR9901.pdf |title=Aircraft Accident Report – Uncontrolled Descent and Collision With Terrain, USAir Flight 427, Boeing 737-300, N513AU, Near Aliquippa, Pennsylvania, September 8, 1994 |id=NTSB/AAR-99-01 |access-date=July 10, 2016 |archive-date=October 14, 2012 |archive-url=https://web.archive.org/web/20121014045026/http://www.ntsb.gov/doclib/reports/1999/AAR9901.pdf |url-status=live}}{{rp|ix}} As a result of the NTSB's findings, the Federal Aviation Administration ordered that the rudder servo valves be replaced on all 737s and mandated new training protocols for pilots to handle an unexpected movement of control surfaces.{{Cite web|url=http://www1.airweb.faa.gov/Regulatory_and_Guidance_Library/rgAD.nsf/WebNewAD/2A37F5FABA444A8086256C4B005A2884?OpenDocument|title=Boeing Model 737 Series Airplanes|website=www1.airweb.faa.gov|access-date=May 21, 2016|archive-url=https://web.archive.org/web/20181007121005/http://www1.airweb.faa.gov/Regulatory_and_Guidance_Library/rgAD.nsf/WebNewAD/2A37F5FABA444A8086256C4B005A2884?OpenDocument|archive-date=October 7, 2018|url-status=dead}}

Following the crashes of two 737 MAX 8 aircraft, Lion Air Flight 610 in October 2018 and Ethiopian Airlines Flight 302 in March 2019, which caused 346 deaths, civil aviation authorities around the world grounded the 737 MAX series. On December 16, 2019, Boeing announced that it would suspend production of the 737 MAX from January 2020. Production of the MAX series resumed on May 27, 2020.{{Cite web|title=Boeing Resumes 737 MAX Production|url=https://boeing.mediaroom.com/news-releases-statements?item=130685|access-date=January 10, 2021|website=MediaRoom|archive-date=January 12, 2021|archive-url=https://web.archive.org/web/20210112050500/https://boeing.mediaroom.com/news-releases-statements?item=130685|url-status=live}}

{{incomplete list|date=August 2024}}

File:Tukwila, WA, USA - panoramio (11).jpg 737-200 N213US fuselage section at the Museum of Flight]]

Owing to the 737's long production history and popularity, many older 737s have found use in museums after reaching the end of useful service.

• 19437/1: 737-130 registered N515NA on static display at the Museum of Flight in Seattle, Washington. It was the first 737 built and is painted in NASA markings.{{cite web|title=Boeing 737-130|url=http://www.museumofflight.org/aircraft/boeing-737-130|website=The Museum of Flight|access-date=March 24, 2017|archive-date=April 24, 2017|archive-url=https://web.archive.org/web/20170424155037/http://www.museumofflight.org/aircraft/boeing-737-130|url-status=live}}
• 19047/14: 737-222 registered N9009U preserved by Southern Illinois University Carbondale at Southern Illinois Airport.{{Citation needed|date=August 2024}}
• 20213/160: 737-201 registered N213US forward fuselage on static display at the Museum of Flight in Seattle, Washington, in USAir livery.{{cite web |title=N213US |url=https://www.jetphotos.com/photo/11343696 |website=Jetphotos |access-date=30 November 2024 |date=19 March 2024}}
• 20561/292: 737-281 registered LV-WTX on static display at the National Museum of Aeronautics in Morón, Buenos Aires.{{Citation needed|date=August 2024}}
• 20562/293: 737-281 registered CC-CSK fuselage preserved at Motel Bahía in Concón, Chile.{{cite web |url=http://modocharlie.com/2012/12/trasladaron-el-boeing-737-200-al-motel-en-concon/ |title=Trasladaron el Boeing 737-200 al motel en Concón (Actualizado con fotos) |website=ModoCharlie |access-date=July 11, 2018 |date=December 24, 2012 |archive-date=July 12, 2018 |archive-url=https://web.archive.org/web/20180712025109/http://modocharlie.com/2012/12/trasladaron-el-boeing-737-200-al-motel-en-concon/ |url-status=live}}
• 21262/470: 737-2H4 registered C-GWJT on static display at the British Columbia Institute of Technology Aerospace Technology Campus in Richmond, British Columbia. It is used for ground instructional training. The aircraft was donated by WestJet and bears its livery.{{cite web|title=WestJet donates 737-200 aircraft to BCIT Aerospace |url=https://www.bcit.ca/news/releases/newsrelease100103101.shtml |website=BCIT|access-date=March 24, 2017 |archive-url=https://web.archive.org/web/20040703001512/http://www.bcit.ca/news/releases/newsrelease100103101.shtml |archive-date=July 3, 2004|date=October 1, 2003}}
• 21340/499: 737-2H4 registered N29SW on static display at the Kansas Aviation Museum in Wichita, Kansas. It was formerly operated by Ryan International Airlines and prior to that Southwest Airlines.{{cite web|title=Boeing 737-200|url=http://kansasaviationmuseum.org/visit/aircraft/boeing-737-200|website=Kansas Aviation Museum|access-date=March 24, 2017|date=June 11, 2014|archive-date=January 21, 2017|archive-url=https://web.archive.org/web/20170121141528/http://kansasaviationmuseum.org/visit/aircraft/boeing-737-200/|url-status=live}}
• 21712/557: 737-275 registered C-GIPW preserved in operational condition at Alberta Flying Heritage Museum in Villeneuve, Alberta. Painted in Pacific Western Airlines livery.{{Citation needed|date=August 2024}}
• 22578/767: 737-290C registered N740AS on static display at the Alaska Aviation Heritage Museum in Anchorage, Alaska. It was formerly operated by Alaska Airlines.{{cite web |title=Alaska Aviation Museum, Lake Hood, Anchorage |url=https://www.rodbearden.com/Alaska%202022/Alaska%20Aviation%20Museum/Index.htm#Boeing%20737-290C-Adv%20Alaska%20Airlines%20N740AS%2010 |website=Rod's Aviation Photos |access-date=30 November 2024 |date=5 May 2022}}
• 22826/878: 737-2H4 registered YV1361 preserved at a hotel in Santiago, Chile. It was formerly operated by Avior Airlines.{{Citation needed|date=August 2024}}
• 23059/980: 737-2Z6 registered 22–222 on static display at the Royal Thai Air Force Museum in Bangkok.{{cite web |title=ROYAL THAI AIR FORCE MUSEUM, DON MUEANG |url=http://media.wix.com/ugd/3b4903_e391b568c5ec448085dad18a1ecde460.pdf |access-date=March 24, 2017 |date=December 26, 2016 |archive-date=March 4, 2017 |archive-url=https://web.archive.org/web/20170304114831/http://media.wix.com/ugd/3b4903_e391b568c5ec448085dad18a1ecde460.pdf |url-status=live}}
• 22940/1037: 737-3H4 registered N300SW on static display at the Frontiers of Flight Museum in Dallas, Texas. It was the first such aircraft delivered to Southwest Airlines in November 1984.{{cite web|title=Boeing 737-300|url=http://www.flightmuseum.com/aircraft-3/boeing-737-300|website=Frontiers of Flight Museum|access-date=March 24, 2017|date=June 23, 2012|archive-date=March 25, 2017|archive-url=https://web.archive.org/web/20170325025550/http://www.flightmuseum.com/aircraft-3/boeing-737-300/|url-status=live}}
• 23257/1124: 737-301 registered PK-AWU on static display at ITE College Central in Singapore.{{Citation needed|date=August 2024}}
• 23472/1194: 737-219 registered ZS-SMD on static display at the South African Airways Museum in Germiston, Gauteng.{{cite web |title=Pukeko |url=http://www.saamuseum.co.za/our-aircraft/102.html |website=SAA Museum Society |access-date=March 24, 2017 |archive-date=December 15, 2016 |archive-url=https://web.archive.org/web/20161215032054/http://saamuseum.co.za/our-aircraft/102.html |url-status=live}}
• 23660/1294: 737-377 registered G-CELS (nickname Elsie) on static display at Norwich International Aviation Academy, as an aircraft maintenance trainer. It is painted in the silver & red Jet2.com color scheme, without the logo branding.{{Cite web |url=http://www.civilianaviation.co.uk/forum/viewtopic.php?f=60&t=26336 |title=Civilian Aviation • Home to the Civil Aviation Enthusiast • View topic – G-CELS Boeing 737-300 |website=www.civilianaviation.co.uk |language=en-gb |access-date=March 17, 2018 |archive-date=March 17, 2018 |archive-url=https://web.archive.org/web/20180317233014/http://www.civilianaviation.co.uk/forum/viewtopic.php?f=60&t=26336 |url-status=live}}
• 27286/2528: 737-3Q8 registered N759BA on static display at the Pima Air & Space Museum in Tucson, Arizona. It is painted in China Southern Airlines markings, and was previously operated by the airline as B-2921.{{cite web |title=Boeing 737-3Q8 |url=https://pimaair.org/museum-aircraft/boeing-737-300/ |website=Pima Air & Space Museum |access-date=1 December 2024}}

{{sticky header}}

{{Notelist}}

{{aircontent

|see also=

|related=

{{div col|colwidth=15em}}

• Boeing 737 AEW&C
• Boeing 737 Classic
• Boeing 737 MAX
• Boeing 737 Next Generation
• Boeing Business Jet
• Boeing C-40 Clipper
• Boeing P-8 Poseidon
• Boeing T-43

{{div col end}}

|similar aircraft=

{{div col|colwidth=15em}}

• Airbus A220
• Airbus A320 family
• Boeing 717
• Comac C919
• Dassault Mercure
• Embraer 195
• McDonnell Douglas DC-9
• McDonnell Douglas MD-80
• McDonnell Douglas MD-90
• Sukhoi Superjet 100
• Yakovlev Yak-42D

{{div col end}}

|lists=

}}

{{Reflist}}

{{Refbegin}}

• {{cite book |last1=Anderson |first1=David F. |last2=Eberhardt |first2=Scott |year=2009 |title=Understanding Flight |url=https://books.google.com/books?id=wmuPXQuZnGoC |location=Chicago |publisher=McGraw Hill Professional |isbn=978-0-07-162696-5 |access-date=October 14, 2015 |archive-date=October 16, 2015 |archive-url=https://web.archive.org/web/20151016201845/https://books.google.com/books?id=wmuPXQuZnGoC |url-status=live}}
• {{cite book |last1=Brady |first1= Chris |date=October 17, 2014 |title=The Boeing 737 Technical Guide (Pocket Budget Version) |publisher=Lulu Enterprises |isbn=978-1-291-77318-7}}{{verify source|date=April 2022}}
• {{Cite book |last1=Brady |first1= Chris |year=2017 |title=The Boeing 737 Technical Guide |location=Kingsley, Frodsham, Cheshire, UK |publisher=Tech Pilot Services |isbn=978-1-4475-3273-6}}
• {{cite book |last=Bowers |first=Peter M. |year=1989 |title=Boeing Aircraft Since 1916 |location=Annapolis, Md. |publisher=Naval Institute Press |isbn=978-0-87021-037-2}}
• {{cite book |last=Endres |first=Günter |year=2001 |title=The Illustrated Directory of Modern Commercial Aircraft |location=St. Paul, Minn. |publisher=MBI Publishing Company |isbn=978-0-7603-1125-7}}
• {{cite book |last=Garvin |first=Robert V. |year=1998 |title=Starting Something Big: The Commercial Emergence of GE Aircraft Engines |location=Reston, VA |publisher=American Institute of Aeronautics and Astronautics |isbn=1-56347-289-9}}
• {{cite book |last1=Redding |first1=Robert |last2=Yenne |first2=Bills |year=1997 |title=Boeing: Planemaker to the World |location=Berkeley, Cal. |publisher=Thunder Bay Pres |isbn=978-1-57145-045-6}}
• {{cite book |last1=Sharpe |first1=Michael |last2=Shaw |first2=Robbie |year=2001 |title=Boeing 737-100 and 200 |location=St. Paul, Minn. |publisher=MBI Publishing Company |isbn=978-0-7603-0991-9 |url-access=registration |url=https://archive.org/details/boeing737100200a00mich}}
• {{cite book |last=Shaw |first=Robbie |year=1995 |title=Boeing Jetliners |location=London |publisher=Osprey Aerospace |isbn=978-1-85532-528-9}}
• {{cite book |last=Shaw |first=Robbie |year=1999 |title=Boeing 737-300 to -800 |location=St. Paul, Minnesota |publisher=MBI Publishing Company |isbn=978-0-7603-0699-4}}
• {{cite book |last=Sutter |first=Joe |year=2006 |title=747: Creating the World's First Jumbo Jet and Other Adventures from a Life in Aviation |location=Washington, D.C. |publisher=Smithsonian Books |isbn=978-0-06-088242-6}}

{{Refend}}

{{Commons}}

• [http://www.boeing.com/commercial/737family/background.html 737 page on Boeing.com]
• [http://www.flightglobal.com/news/articles/the-boeing-737-story-204410/ The 737 Story on FlightInternational.com]
• {{cite web |url= http://www.boeing.com/resources/boeingdotcom/company/about_bca/startup/pdf/historical/737-200-passenger.pdf |title= 737-200 |date= 2007 |publisher= Boeing}}

{{Boeing airliners}}

{{Boeing 737 family}}

{{Boeing 7x7 timeline}}

{{Boeing model numbers}}

{{Thai transport aircraft designations}}

{{FAB aircraft designations}}

{{Authority control}}

Category:Aircraft first flown in 1967

737

Category:Low-wing aircraft

Category:Twinjets

Category:1960s United States airliners

Category:Aircraft with retractable tricycle landing gear