The Tupolev I-4 was a Soviet sesquiplane single-seat fighter. It was conceived in 1927 by Pavel Sukhoi as his first aircraft design for the Tupolev design bureau, and was the first Soviet all-metal fighter.
The Vought XF3U was the prototype of a two-seat, all-metal biplane fighter, built by Vought Aircraft Company of Dallas, Texas for the United States Navy.
The Berliner-Joyce XFJ was a United States prototype biplane fighter aircraft that first flew in May 1930. Designed by Berliner-Joyce Aircraft for the United States Navy, its lower wing, placed below the fuselage and just two feet above the ground, apparently gave it a tendency to ground loop when landing, and it was never ordered for production.
The Boeing XF6B-1 / XBFB-1 was Boeing's last biplane design for the United States Navy. Only the one prototype, Model 236, was ever built; although first flying in early 1933, it rammed into a crash barrier in 1936 and the design was not pursued further.
The Boeing XP-15 was an American prototype monoplane fighter.
The Macchi M.39 was a racing seaplane designed and built by the Italian aircraft company Aeronautica Macchi in 1925–26. An M.39 piloted by Major Mario de Bernardi (1893–1959) won the 1926 Schneider Trophy, and the type also set world speed records that year.
The Nakajima E4N was a Japanese shipboard reconnaissance aircraft of the 1930s. It was a two-seat, single-engine, equal-span biplane seaplane used primarily by the Imperial Japanese Navy.
The Fokker B.II was a prototype sesquiplane shipboard reconnaissance flying boat built in the Netherlands in 1923.
The Eberhart XFG was an American single-seat experimental ship-borne biplane fighter aircraft developed for the United States Navy in 1927 by the Eberhart Aeroplane and Motor Company. The sole prototype was rebuilt into the XF2G with the addition of a single float and a different engine, but the aircraft was destroyed in a crash in 1928, and the type did not enter production.
The Levasseur PL.5 was a carrier-based fighter produced in France in the late 1920s, in response to the 1924 AMBC.2 specification issued by the Service Technique de l'Aéronautique (STAé). It was a conventional, single-bay sesquiplane that carried a crew of two in tandem, open cockpits. Like other Levasseur naval designs of the day, it incorporated several safety features in case of ditching at sea. Apart from small floats attached directly to the undersides of the lower wing, the main units of the fixed, tail-skid undercarriage could be jettisoned in flight, and the underside of the fuselage was given a boat-like shape and made watertight.
The Thomas-Morse MB-7 was an American racing plane built by Thomas-Morse Aircraft for the US Navy.
The Wright F2W was an American racing aircraft built by Wright Aeronautical Corporation for the US Navy.
The Verville VCP was an American single-engined biplane fighter aircraft of the 1920s. A single example of the VCP-1 was built by the United States Army Air Service's Engineering Division, which was later rebuilt into a successful racing aircraft, while a second, modified fighter was built as the PW-1.
The Nieuport-Delage Sesquiplans were a series of 1920s French racing monoplanes built by Nieuport-Delage. It established a world air speed record in 1923.
The Tebaldi-Zari was an Italian fighter prototype of 1919. The Breda company later acquired the rights to it.
The Caproni Ca.90 was a prototype Italian heavy bomber designed and built by Caproni. When it first flew in 1929 it was the largest aircraft in the world.
The CAMS 36 was a 1920s French flying boat designed and built by Chantiers Aéro-Maritimes de la Seine. It was originally conceived as a single-seat fighter but evolved as a racer to compete in the 1922 Schneider Trophy race. Lack of funds in 1922 and an accident in 1923 meant the two aircraft built failed to participate in a Schneider race.
The Buscaylet-de Monge 5/2 was a 1920s French single-seat, parasol-wing fighter prototype designed by Louis de Monge for the Buscaylet et Cie company.
The Halberstadt C.VIII was a prototype two-seat general-purpose biplane built by Halberstadt during World War I.
The Kawanishi K6K was a prototype Japanese training aircraft built by the Kawanishi Aircraft Company in the late 1930s.
