airline hub

{{Short description|Airport that an airline uses as a transfer point to get passengers to their intended destination}}

{{See also|List of hub airports}}

{{Use dmy dates|date=September 2024}}

File:Frankfurt airport hub map v2.png and its Star Alliance partners may connect through Frankfurt Airport, Lufthansa's main hub]]

An airline hub or hub airport is an airport used by one or more airlines to concentrate passenger traffic and flight operations. Hubs serve as transfer (or stop-over) points to help get passengers to their final destination.{{efn|Colloquially, an airline hub may be defined as an airport that receives many passengers or as an airport that serves as the operating base of an airline, whether or not the airline allows for connecting traffic.{{cite book |last=Holloway |first=Stephen |date=2008 |title=Straight and Level: Practical Airline Economics |url=https://books.google.com/books?id=8kr50wL0tIYC |edition=3rd |publisher=Ashgate Publishing |pages=376, 378 |isbn=9780754672562 |url-status=live |archive-url=https://web.archive.org/web/20180508005505/https://books.google.com/books?id=8kr50wL0tIYC |archive-date=8 May 2018 }}}}{{efn|The Federal Aviation Administration of the United States defines a hub in terms of passenger enplanements. Specifically, a hub is an airport that handles 0.05% or more of the nation's annual passenger boardings.{{cite web |date=3 March 2016 |title=Airport Categories |url=http://www.faa.gov/airports/planning_capacity/passenger_allcargo_stats/categories/ |publisher=Federal Aviation Administration |access-date=30 May 2016 |url-status=live |archive-url=https://web.archive.org/web/20160528190758/http://www.faa.gov/airports/planning_capacity/passenger_allcargo_stats/categories/ |archive-date=28 May 2016 }}}} It is part of the hub-and-spoke system. An airline may operate flights from several non-hub (spoke) cities to the hub airport, and passengers traveling between spoke cities connect through the hub. This paradigm creates economies of scale that allow an airline to serve (via an intermediate connection) city-pairs that could otherwise not be economically served on a non-stop basis. This system contrasts with the point-to-point model, in which there are no hubs and nonstop flights are instead offered between spoke cities. Hub airports also serve origin and destination (O&D) traffic.

Operations

File:Heathrow Terminal 5C Iwelumo-1.jpg is Heathrow Airport in London]]

The hub-and-spoke system allows an airline to serve fewer routes, so fewer aircraft are needed.{{cite journal |last1=Cook |first1=Gerald |last2=Goodwin |first2=Jeremy |date=2008 |title=Airline Networks: A Comparison of Hub-and-Spoke and Point-to-Point Systems |url=http://commons.erau.edu/cgi/viewcontent.cgi?article=1443&context=jaaer |journal=Journal of Aviation/Aerospace Education & Research |publisher=Embry–Riddle Aeronautical University |volume=17 |issue=2 |pages=52–54 |access-date=28 May 2016 |archive-date=23 September 2015 |archive-url=https://web.archive.org/web/20150923183031/http://commons.erau.edu/cgi/viewcontent.cgi?article=1443&context=jaaer}} The system also increases passenger loads; a flight from a hub to a spoke carries not just passengers originating at the hub, but also passengers originating at multiple spoke cities.{{cite web |title=Airline Deregulation and Hub-and-Spoke Networks |url=https://people.hofstra.edu/geotrans/eng/ch3en/conc3en/hubspokederegulation.html |website=The Geography of Transport Systems |publisher=Hofstra University |access-date=28 May 2016 |archive-date=5 April 2016 |archive-url=https://web.archive.org/web/20160405061213/http://people.hofstra.edu/geotrans/eng/ch3en/conc3en/hubspokederegulation.html}} However, the system is costly. Additional employees and facilities are needed to cater to connecting passengers. To serve spoke cities of varying populations and demand, an airline requires several aircraft types, and specific training and equipment are necessary for each type. In addition, airlines may experience capacity constraints as they expand at their hub airports.{{cite news |last=Schmidt |first=William |date=14 November 1985 |title=Deregulation Challenges Atlanta Airline Hub |url=https://www.nytimes.com/1985/11/14/us/deregulation-challenges-atlanta-airline-hub.html |work=The New York Times |access-date=28 May 2016 |archive-date=24 May 2015 |archive-url=https://web.archive.org/web/20150524170250/http://www.nytimes.com/1985/11/14/us/deregulation-challenges-atlanta-airline-hub.html}}

For the passenger, the hub-and-spoke system offers one-stop air service to a wide array of destinations.{{cite book |last=Lawrence |first=Harry |date=2004 |title=Aviation and the Role of Government |url=https://books.google.com/books?id=30-0qO6WY4AC |publisher=Kendall Hunt |pages=227–228 |isbn=9780757509445 |access-date=30 May 2016 |archive-url=https://web.archive.org/web/20170215200104/https://books.google.com/books?id=30-0qO6WY4AC |archive-date=15 February 2017 |url-status=live }} However, it requires having to regularly make connections en route to their final destination, which increases travel time. Additionally, airlines can come to monopolise their hubs (fortress hubs), allowing them to freely increase fares as passengers have no alternative. High domestic connectivity in the United States is achieved through airport location and hub dominance. The top 10 megahubs in the US are dominated by American Airlines, Delta Air Lines and United Airlines, three of the four largest United States–based airlines.{{cite news |last=Reed |first=Ted |date=18 September 2018 |title=American Airlines Has Hubs at Three of Top Four Most-Connected U.S. Airports, Survey Says |url=https://www.forbes.com/sites/tedreed/2018/09/18/american-airlines-has-hubs-at-three-of-five-most-connected-u-s-airports-survey-says/?sh=61c946866166 |work=Forbes |access-date=27 February 2022}}

=Banking=

Airlines may operate banks of flights at their hubs, in which several flights arrive and depart within short periods of time. The banks may be known as "peaks" of activity at the hubs and the non-banks as "valleys". Banking allows for short connection times for passengers.{{cite news |last=Maxon |first=Terry |date=27 March 2015 |title=American Airlines banking on tighter connections |url=http://www.dallasnews.com/business/airline-industry/20150327-american-airlines-banking-on-tighter-connections.ece |work=The Dallas Morning News |access-date=30 May 2016 |url-status=live |archive-url=https://web.archive.org/web/20160624080652/http://www.dallasnews.com/business/airline-industry/20150327-american-airlines-banking-on-tighter-connections.ece |archive-date=24 June 2016 }} However, an airline must assemble many resources to cater to the influx of flights during a bank, and having several aircraft on the ground at the same time can lead to congestion and delays.{{cite book |editor-last1=Belobaba |editor-first1=Peter |editor-last2=Odoni |editor-first2=Amedeo |editor-last3=Barnhart |editor-first3=Cynthia |date=2016 |title=The Global Airline Industry |url=https://books.google.com/books?id=6WMdCgAAQBAJ |location=Chichester, England |publisher=John Wiley & Sons |pages=142, 172–174 |isbn=9781118881170 |url-status=live |archive-url=https://web.archive.org/web/20180508005505/https://books.google.com/books?id=6WMdCgAAQBAJ |archive-date=8 May 2018 }} In addition, banking could result in inefficient aircraft utilisation, with aircraft waiting at spoke cities for the next bank.{{cite news |last=Reed |first=Dan |date=8 August 2002 |title=American Airlines to try rolling hubs |url=http://usatoday30.usatoday.com/travel/news/2002/2002-08-09-american.htm |work=USA Today |access-date=30 May 2016 |archive-url=https://web.archive.org/web/20161005063049/http://usatoday30.usatoday.com/travel/news/2002/2002-08-09-american.htm |archive-date=5 October 2016 |url-status=live }}

Instead, some airlines have debanked their hubs, introducing a "rolling hub" in which flight arrivals and departures are spread throughout the day. This phenomenon is also known as "depeaking". While costs may decrease, connection times are longer at a rolling hub. American Airlines was the first to depeak its hubs, trying to improve profitability following the September 11 attacks. It rebanked its hubs in 2015, however, feeling the gain in connecting passengers would outweigh the rise in costs.

For example, the hub of Qatar Airways in Doha Airport has 471 daily movements to 140 destinations by March 2020 with an average of 262 seats per movement; in three main waves: 05:00–09:00 (132 movements), 16:00–21:00 (128) and 23:00–03:00 (132), allowing around 30 million connecting passengers in 2019.{{cite news |url= https://www.anna.aero/2020/03/09/qatar-airways-doha-hub-analysed-three-waves-471-movements-today/ |date= 9 March 2020 |title= Qatar Airways' Doha hub analysed; three waves & 471 movements today |work= Airline Network News & Analysis |access-date= 13 March 2020 |archive-url= https://web.archive.org/web/20200321030251/https://www.anna.aero/2020/03/09/qatar-airways-doha-hub-analysed-three-waves-471-movements-today/ |archive-date= 21 March 2020 |url-status= live }}

History

=United States=

Before the US airline industry was deregulated in 1978, most airlines operated under the point-to-point system (with a notable exception being Pan Am). The Civil Aeronautics Board dictated which routes an airline could fly. At the same time, however, some airlines began to experiment with the hub-and-spoke system. Delta Air Lines was the first to implement such a system, providing service to remote spoke cities from its Atlanta hub. After deregulation, many airlines quickly established hub-and-spoke route networks of their own.

class="wikitable sortable"

|+ US major top 20 airports, millions of departing passengers, 2022{{cite news |url= https://www.afar.com/magazine/busiest-airports-in-the-us |title= These Are the 20 Busiest Airports in the United States |date= 28 August 2023 |access-date= 13 November 2023 |work= AFAR }}{{cite web |url=https://www.transtats.bts.gov/Data_Elements.aspx?Data=4 |title= USDOT Bureau of Transpoirtation Statistics Data Elements |publisher= United States Department of Transportation |access-date= 13 November 2023 }}

! Airport !! Region {{citation needed|date=May 2021}} !! 2022 pax.

! AA !! DL !! UA

!WN

Atlanta

| South|| 45.37

| || 33.87 ||

|3.68

Dallas/Fort Worth

| South || 35.33

| 24.34 || ||

|

Denver

| West|| 33.75

| || || 12.34

|10.43

Chicago–O'Hare

| Midwest|| 33.13

| 7.71 || || 11.13

|

Los Angeles

| West || 32.29

| 4.91 || 5.42 || 4.74

|3.21

New York–JFK

| Northeast || 26.99

| 3.37 || 6.23 ||

|

Las Vegas

| West

| 25.26

|

|

|

| 8.87

Orlando

| South

| 24.44

|

|

|

| 4.79

Miami

| South || 23.68

| 13.93 || ||

|

Charlotte

| South || 23.09

| 16.14 || ||

|

Seattle/Tacoma{{efn|Alaska Airlines: 11.4{{cite web|title=Sea–Tac Airport Annual Activity Report|url=https://public.tableau.com/profile/portofseattlebi#!/vizhome/Sea-TacAirportActivityReportTP/Cover|publisher=Port of Seattle|access-date=22 July 2018|date=15 April 2018|archive-url=https://web.archive.org/web/20180722155726/https://public.tableau.com/profile/portofseattlebi#!/vizhome/Sea-TacAirportActivityReportTP/Cover|archive-date=22 July 2018|url-status=live}}}}

| West || 22.11

| || 4.47 ||

|

Phoenix–Sky Harbor

| West || 21.79

| 7.39 || ||

| 7.62

Newark

| Northeast || 21.66

| || || 12.15

|

San Francisco

| West || 20.40

| || || 8.50

|

Houston–Intercontinental

| South || 19.80

| || || 11.08

|

Boston

| Northeast || 15.42

| || 3.26 ||

|

Fort Lauderdale

| South

| 15.36

|

|

|

|

Minneapolis/St. Paul

| Midwest || 15.20

| || 8.52 ||

|

New York–LaGuardia

| Northeast || 14.36

| 2.49 || 2.92 ||

|

Detroit

| Midwest || 13.73

| || 7.95 ||

|

=Middle East=

File:Emirates tails (8499979565).jpg aircraft at Dubai International Airport]]

In 1974, the governments of Bahrain, Oman, Qatar and the United Arab Emirates took control of Gulf Air from the British Overseas Airways Corporation (BOAC). Gulf Air became the flag carrier of the four Middle Eastern nations. It linked Oman, Qatar and the UAE to its Bahrain hub, from which it offered flights to destinations throughout Europe and Asia. In the UAE, Gulf Air focused on Abu Dhabi rather than Dubai, contrary to the aspirations of UAE Prime Minister Mohammed bin Rashid Al Maktoum to transform the latter into a world-class metropolis. Sheikh Mohammed proceeded to establish a new airline based in Dubai, Emirates, which launched operations in 1985.{{cite thesis |last=Al-Sayeh |first=Karim |date=2014 |title=The Rise of the Emerging Middle East Carriers: Outlook and Implications for the Global Airline Industry |degree=MSc |pages=25–26, 28 |publisher=Massachusetts Institute of Technology |url=https://dspace.mit.edu/bitstream/handle/1721.1/89852/890140089-MIT.pdf?sequence=2 |access-date=28 May 2016 |archive-date=29 May 2016 |archive-url=https://web.archive.org/web/20160529165854/https://dspace.mit.edu/bitstream/handle/1721.1/89852/890140089-MIT.pdf?sequence=2}}

Elsewhere in the Middle East region, Qatar and Oman decided to create their own airlines as well. Qatar Airways and Oman Air were both founded in 1993, with hubs at Doha and Muscat respectively. As the new airlines grew, their home nations relied less on Gulf Air to provide air service. Qatar withdrew its share in Gulf Air in 2002. In 2003, the UAE formed another national airline, Etihad Airways, which is based in Abu Dhabi. The country exited Gulf Air in 2006, and Oman followed in 2007. Gulf Air therefore became fully owned by the government of Bahrain.

Emirates, Qatar Airways, Saudia and Etihad Airways have since established large hubs at their respective home airports. The hubs, which benefit from their proximity to large population centres, have become popular stopover points on trips between Europe and Asia, for example.{{cite news |last=Kindergan |first=Ashley |date=2 January 2015 |title=Revisiting: The Rise of the Gulf Carriers |url=https://www.thefinancialist.com/the-rise-of-the-gulf-carriers/ |website=The Financialist |publisher=Credit Suisse |access-date=28 May 2016 |archive-date=21 April 2016 |archive-url=https://web.archive.org/web/20160421112721/https://www.thefinancialist.com/the-rise-of-the-gulf-carriers/}} Their rapid growth has impacted the development of traditional hubs, such as London-Heathrow, Paris-Charles de Gaulle, and New York-JFK.{{cite news |last=Dewey |first=Caitlin |date=5 March 2013 |title=The changing geography of international air travel |url=https://www.washingtonpost.com/news/worldviews/wp/2013/03/05/the-changing-geography-of-international-air-travel/ |newspaper=The Washington Post |access-date=28 May 2016 |url-status=live |archive-url=https://web.archive.org/web/20160808124725/https://www.washingtonpost.com/news/worldviews/wp/2013/03/05/the-changing-geography-of-international-air-travel/ |archive-date=8 August 2016 }}

Types of hubs

=Cargo hubs and scissor hubs=

A cargo hub is an airport that primarily is operated by a cargo airline that uses the hub-and-spoke system. In the United States, two of the largest cargo hub airports, FedEx's Memphis Superhub and UPS Louisville Worldport, are close to the mean center of the United States population. FedEx's airline, FedEx Express, established its Memphis hub in 1973, prior to the deregulation of the air cargo industry in the United States. The system has created an efficient delivery system for the airline.{{cite report |author-last=Scholes |author-first=Kevan |date=2004 |title=Federal Express – delivering the goods |url=http://wps.pearsoned.co.uk/wps/media/objects/1669/1709610/extra_cases/0273687395_case_fedex.pdf |publisher=Pearson PLC |access-date=29 May 2016 |archive-date=11 June 2014 |archive-url=https://web.archive.org/web/20140611080516/http://wps.pearsoned.co.uk/wps/media/objects/1669/1709610/extra_cases/0273687395_case_fedex.pdf}} UPS Airlines has followed a similar pattern in Louisville. In Europe, ASL Airlines, Cargolux and DHL Aviation follow a similar strategy and operate their primary hubs at Liège, Luxembourg and Leipzig respectively.{{cite web |title=Hubs of Major Air Freight Integrators |url=https://people.hofstra.edu/geotrans/eng/ch5en/appl5en/upshubs.html |website=The Geography of Transport Systems |publisher=Hofstra University |access-date=29 May 2016 |archive-date=12 April 2016 |archive-url=https://web.archive.org/web/20160412073131/http://people.hofstra.edu/geotrans/eng/ch5en/appl5en/upshubs.html}}

Additionally, Ted Stevens International Airport in Anchorage, Alaska, is a frequent stop-over hub for many cargo airlines flying between Asia and North America. Most cargo airlines only stop in Anchorage for refueling and customs, but FedEx and UPS frequently use Anchorage to sort trans-pacific packages between regional hubs on each continent in addition to refueling and customs.{{Cite web|last=Denby|first=Sam|date=13 February 2018|title=How Overnight Shipping Works|url=https://www.youtube.com/watch?v=y3qfeoqErtY |archive-url=https://ghostarchive.org/varchive/youtube/20211213/y3qfeoqErtY |archive-date=2021-12-13|url-status=live|access-date=4 March 2021|via=YouTube}}{{cbignore}}

Passenger airlines that operate in a similar manner to the FedEx and UPS hubs are often regarded as scissor hubs, as many flights to one destination all land and deplane passengers simultaneously and, after a passenger transit period, repeat a similar process for departure to the final destination of each plane.{{cite news|last=McWhirter|first=Alex|date=27 November 2015|title=Jet Airways to axe Brussels hub|work=Business Traveller|url=http://www.businesstraveller.com/news/102316/jet-airways-to-axe-brussels-hub|access-date=29 May 2016|archive-url=https://web.archive.org/web/20151212103026/http://www.businesstraveller.com/news/102316/jet-airways-to-axe-brussels-hub|archive-date=12 December 2015}} In past, Air India operated a scissor hub at London's Heathrow Airport, where passengers from Delhi, Ahmedabad, and Mumbai could continue onto a flight to Newark.{{cite web|title=Ahmedabad to Newark via London|url=http://www.airindia.in/ahmedabad-to-newark-via-london.htm|url-status=live|archive-url=https://web.archive.org/web/20180307023029/http://www.airindia.in/Ahmedabad-to-Newark-via-London.htm|archive-date=7 March 2018|access-date=8 May 2018|website=airindia.in}} Until its grounding, Jet Airways operated a similar scissor hub at Amsterdam Airport Schiphol to transport passengers from Bangalore, Mumbai and Delhi to Toronto-Pearson and vice versa. At the peak of operations at their former scissor hub at Brussels prior to the 2016 shift to Schiphol, flights operated from Mumbai, Delhi, and Chennai and continued onward to Toronto, New York, and Newark after a near-simultaneous stopover in Brussels and vice versa.{{Cite web|last=André Orban|date=2016-03-27|title=Jet Airways officially launches flights from Amsterdam Schiphol|url=https://www.aviation24.be/airlines/jet-airways/jet-airways-officially-launches-flight-amsterdam-schiphol/|access-date=2021-12-11|website=Aviation24.be}} An international scissor hub could be used for third and fourth freedom flights or it could be used for fifth freedom flights, for which a precursor is a bilateral treaty between two country pairs.

WestJet used to utilize St. John's as a scissor hub during its summer schedule for flights inbound from Ottawa, Toronto, and Orlando and outbound to Dublin and London–Gatwick. Qantas similarly used to utilize Los Angeles International Airport as a scissor hub for flights inbound from Melbourne, Brisbane or Sydney, where passengers could connect onwards if traveling to New York–JFK.

=Focus city=

File:Airbus A320-232, JetBlue Airways AN0529077.jpg are Boston, Fort Lauderdale, Los Angeles, New York–JFK, Orlando, and San Juan.{{cite web |title=The JetBlue focus cities |url=http://mediaroom.jetblue.com/~/media/Files/J/Jetblue-IR/fact-sheet-documents/jetblue-focus-cities.pdf |work=JetBlue |access-date=26 May 2016 |archive-url=https://web.archive.org/web/20150218210947/http://mediaroom.jetblue.com/~/media/Files/J/Jetblue-IR/fact-sheet-documents/jetblue-focus-cities.pdf |archive-date=18 February 2015 }}]]

In the airline industry, a focus city is a destination from which an airline operates limited point-to-point routes.{{cite encyclopedia |last=Mammarella |first=James |editor-last=Garrett |editor-first=Mark |title=Airport Hubs |encyclopedia=Encyclopedia of Transportation: Social Science and Policy |year=2014 |publisher=SAGE Publications |isbn=978-1-4522-6779-1 |url=https://books.google.com/books?id=0p-kBQAAQBAJ |url-status=live |archive-url=https://web.archive.org/web/20180508005505/https://books.google.com/books?id=0p-kBQAAQBAJ |archive-date=8 May 2018 }} A focus city primarily caters to the local market rather than to connecting passengers.{{cite news |last=Heilman |first=Wayne |date=20 April 2012 |title=Springs is Frontier's new front in battle for Colorado travelers |url=http://gazette.com/springs-is-frontiers-new-front-in-battle-for-colorado-travelers/article/137275 |work=The Gazette (Colorado Springs) |access-date=26 May 2016 |archive-url=https://web.archive.org/web/20160526231749/http://gazette.com/springs-is-frontiers-new-front-in-battle-for-colorado-travelers/article/137275 |archive-date=26 May 2016}}{{cite news |last=Mutzabaugh |first=Ben |date=3 March 2006 |title=United adds a 'hublet' in San Antonio |url=http://usatoday30.usatoday.com/travel/flights/2006-03-02-united-sanantonio_x.htm |newspaper=USA Today|publisher=Gannett|location=McLean |access-date=26 May 2016 |archive-url=https://web.archive.org/web/20160526231909/http://usatoday30.usatoday.com/travel/flights/2006-03-02-united-sanantonio_x.htm |archive-date=26 May 2016}}

Although the term focus city is used to mainly refer to an airport from which an airline operates limited point-to-point routes, its usage has loosely expanded to refer to a small-scale hub as well.{{cite encyclopedia |last=Mammarella |first=James |editor-last=Garrett |editor-first=Mark |title=Airport Hubs |encyclopedia=Encyclopedia of Transportation: Social Science and Policy |year=2014 |publisher=SAGE Publications |isbn=9781452267791 |url=https://books.google.com/books?id=0p-kBQAAQBAJ |url-status=live |archive-url=https://web.archive.org/web/20180508005505/https://books.google.com/books?id=0p-kBQAAQBAJ |archive-date=8 May 2018 }} For example, even though JetBlue's operations at New York–JFK resemble that of a hub, the airline still refers to it as a focus city.

=Fortress hub=

A fortress hub refers to an airport where a single airline dominates the market share, making it challenging for competitors to establish a foothold.{{cite book |last1=Rose |first1=Mark |last2=Seely |first2=Bruce |last3=Barrett |first3=Paul |date=2006 |title=The Best Transportation System in the World: Railroads, Trucks, Airlines, and American Public Policy in the Twentieth Century |url=https://books.google.com/books?id=ept0BAAAQBAJ |location=Columbus, Ohio |publisher=Ohio State University |page=233 |isbn=9780812221169 |url-status=live |archive-url=https://web.archive.org/web/20180508005505/https://books.google.com/books?id=ept0BAAAQBAJ |archive-date=8 May 2018 }} This term is commonly used in the United States, where the airlines with the largest fortress hubs are Delta Air Lines at Hartsfield–Jackson Atlanta International Airport and American Airlines at Dallas Fort Worth International Airport.

Most national flag carriers maintain a similarly dominant presence at their countries’ primary international airport, benefiting from historical advantages and market influence. Examples include:

=Primary and secondary hubs=

A primary hub is the main hub for an airline. However, as an airline expands operations at its primary hub to the point that it experiences capacity limitations, it may elect to open secondary hubs. Examples of such hubs are Air Canada's hubs at Montréal–Trudeau and Vancouver, British Airways' hub at London–Gatwick, Air India's hub at Mumbai and Lufthansa's hub at Munich. By operating multiple hubs, airlines can expand their geographic reach.{{cite book |last1=Thompson |first1=David |last2=Perkins |first2=Stephen |last3=van Dender |first3=Kurt |last4=Zupan |first4=Jeffrey |last5=Forsyth |first5=Peter |last6=Yamaguchi |first6=Katsuhiro |last7=Niemeier |first7=Hans-Martin |last8=Burghouwt |first8=Guillaume |date=2014 |title=Expanding Airport Capacity in Large Urban Areas |url=https://books.google.com/books?id=ZzvjAwAAQBAJ |publisher=OECD Publishing |issue=153 |pages=151–152 |doi=10.1787/2074336x |access-date=29 May 2016 |isbn=9789282107393 |series=ITF Round Tables |url-status=live |archive-url=https://web.archive.org/web/20180508005505/https://books.google.com/books?id=ZzvjAwAAQBAJ |archive-date=8 May 2018 }} They can also better serve spoke–spoke markets, providing more itineraries with connections at different hubs.

Cargo airlines like FedEx Express and UPS Airlines also operate secondary hubs to an extent, but these are primarily used to serve regional high-demand destinations because shipping packages through its main hub would waste fuel; an example of this would be FedEx transiting a package through Oakland International Airport when shipping packages between destinations near Seattle and Phoenix, Arizona instead of sending deliveries through the Memphis Superhub.

=Reliever hub=

A given hub's capacity may become exhausted or capacity shortages may occur during peak periods of the day, at which point airlines may be compelled to shift traffic to a reliever hub. A reliever hub has the potential to serve several functions for an airline: it can bypass the congested hub, it can absorb excess demand for flights that could otherwise not be scheduled at the congested hub, and it can schedule new O&D city pairs for connecting traffic.

One of the most recognized examples of this model is Delta Air Lines' and American Airlines' uses of LaGuardia Airport as a domestic hub in New York City, due to capacity and slot restrictions at their hubs at John F. Kennedy International Airport. Many regional flights operate out of LaGuardia, while most international and long-haul domestic flights remain at JFK.

Lufthansa operates a similar model of business with its hubs at Frankfurt Airport and Munich Airport. Generally speaking, a marginal majority of the airline's long-haul flights are based out of Frankfurt, while a similarly sized but smaller minority are based out of Munich.

=Moonlight hub=

In past history, carriers have maintained niche, time-of-day operations at hubs. The most notable was America West's use of Las Vegas as a primary night-flight hub to increase aircraft utilization rates far beyond those of competing carriers.

See also

Notes

{{Notelist}}

References

{{Reflist}}

{{Commercial aviation}}

{{DEFAULTSORT:Airline hub}}

Category:Civil aviation