Flettner

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Anton Flettner, Flugzeugbau GmbH was a German helicopter and autogyro manufacturer during World War II, founded by Anton Flettner.{{Cite book |last1=Hirschel |first1=Ernst Heinrich |url=https://books.google.com/books?id=eJ7oCAAAQBAJ |title=Aeronautical Research in Germany: From Lilienthal until Today |last2=Prem |first2=Horst |last3=Madelung |first3=Gero |date=2012-12-06 |publisher=Springer Science & Business Media |isbn=978-3-642-18484-0 |pages=299–300 |language=en}}

Flettner aircraft included:

• Flettner Fl 184 - Reconnaissance autogyro, prototype{{Cite book |last=Griehl |first=Manfred |url=https://books.google.com/books?id=_bFfLGeQZNMC |title=X-Planes: German Luftwaffe Prototypes 1930-1945 |date=2012-10-24 |publisher=Pen and Sword |isbn=978-1-78303-419-2 |pages=264–269 |language=en}}
• Flettner Fl 185 - Reconnaissance helicopter, prototype
• Flettner Fl 265 - Reconnaissance helicopter, prototype
• Flettner Fl 282 Kolibri (Hummingbird) - Reconnaissance helicopter
• Flettner Fl 339 - Reconnaissance helicopter, project
• Flettner Gigant - Experimental helicopter

Anton Flettner's interest in aerodynamics (specifically the Magnus effect, which produces a force from a cylinder rotating in a fluid flow) also led him to invent the Flettner rotor which he used to power a Flettner ship which crossed the Atlantic, and the Flettner ventilator which is still widely used as a cooling device for buses, vans and other commercial vehicles and which is based upon the Savonius principle.