The Aero Letňany A.10 was a biplane airliner produced in Czechoslovakia shortly after World War I. It was the first commercial aircraft to be built in Czechoslovakia and was known as the Ae-10 Limousine. It was designed by Husnik and Vlasak and was intended to meet the growing need for aerial communication to and from the country. Behind the single nose-mounted engine was a cabin with seats for three and two tables, upholstered on the underside, and able to be inverted to provide another two seats if required. A double skinned firewall between the engine and cabin, together with double skinned surfaces to the walls, floor and roof and Triplex windows gave a (relatively) quiet ride. A rear window gave communication with the pilot, whose open cockpit was above and behind the cabin. The cockpit also accommodated the navigator who had a seat directly behind the pilot.
The Polikarpov I-3 was a Soviet fighter designed during the late 1920s. It entered service in 1929, but was retired in 1935 with the advent of fighters with higher performance.
The Rumpler D.I was a fighter-reconnaissance aircraft produced in Germany at the end of World War I. It was a conventional single-bay biplane with wings of unequal span braced by I-struts. It featured an open cockpit and a fixed, tailskid undercarriage. The upper wing was fitted with aerodynamically balanced ailerons and fuselage had an oval cross-section.
The de Havilland DH.42 Dormouse and its two variants the de Havilland Dingo I and II were two-seat single-engined biplanes designed for fighter-reconnaissance and army cooperation roles. They did not achieve production.
The Parnall Pike was a 2/3-seat biplane reconnaissance aircraft, capable of operating off carrier decks or from water, built to an Air Ministry specification in 1927. Only one was constructed.
P.Z.L. P.8 was a fighter designed by Ing. Zygmunt Puławski and constructed by P.Z.L. from 1930.
The Wibault 8 or Wib 8 Simoun (Simoon) was a tandem seat, parasol wing fighter aircraft designed and built in France to a 1925 specification which was later withdrawn; only one Wib 8 was completed.
The Wibault 12 Sirocco or Wib 12 Sirocco was a two-seat, parasol wing fighter aircraft designed and built in France in the 1920s. Three fighter prototypes were completed, one for the RAF and two Army co-operation variants. There was no series production.
The Wibault 13C.1 Trombe (Whirlwind), later known as the Wib 130C.1 Trombe was a single seat, parasol wing lightweight fighter aircraft designed and built in France in the 1920s. It was developed into the more powerful Wib 170C.1 Tornade (Tornado) but government interest in lightweight fighters soon waned.
The Hanriot HD.15 was a French two seat fighter aircraft fitted with a supercharger for good high altitude performance, built in the 1920s. Three were ordered by Japan but lost at sea during delivery.
The Hanriot H.26 was a French single seat fighter aircraft prototype completed in 1923. Only one was built.
The Hanriot H.31 was a single engine, single seat French biplane fighter aircraft built in 1925 to compete in a government programme. It was not successful and only one prototype was completed.
The Bonomi BS.10 Ardea was an Italian single seat high performance glider, designed and built in the mid-1930s. Only one was built.
The Potez 35 was a twin engine bomber aircraft, designed and built in France in the late 1920s. Only one was completed.
The Descamps 17 A.2 was a two-seat reconnaissance fighter built under a French government programme of 1923. Two versions, with different engines, were tested and six examples were built under licence by Caudron as the Caudron C.17 A.2.
The de Marçay 4 was a single seat monoplane fighter built in France in 1923 for a government competition. It did not receive a production contract.
The Les Mureaux 3 C.2 and Les Mureaux 4 C.2 were French two seat, parasol winged fighters, flown in 1927-8, which differed only in their engines. They were developed into near identical army co-operation types, the ANF Les Mureaux 130 A.2 and ANF Les Mureaux 131 A.2, in 1929-31.
The Villiers 26 was a French naval seaplane which used Handley Page slats to provide the wide speed range required for escort and patrol duties. It was tested, behaved satisfactorily but received no production order.
The Régnier 12 was a 1930s Belgian touring aircraft offering variants with different engines and seating plans. Only one was built.
The Caproni Ca.66 and Caproni Ca.67 were Italian night bomber aircraft designed to re-equip the post-World War I Regia Aeronautica.
