The LWS-2 was the Polish air ambulance aircraft prototype, designed in the late-1930s in the LWS factory.
The PZL.16 was a Polish passenger aircraft, designed in the early 1930s in the PZL in Warsaw. It remained a prototype.
The Bellanca 31-40 Senior Pacemaker and its derivatives were a family of a six- and eight-seat utility aircraft built in the United States in the late 1930s. They were the final revision of the original late 1920s Wright-Bellanca WB-2 design. The model numbers used by Bellanca in this period reflected the wing area and engine horsepower, each divided by ten. Like their predecessors, these were high-wing braced monoplanes with conventional tailwheel undercarriage.
The Curtiss-Wright CW-15 Sedan was a four-seat utility aircraft produced in small numbers in the United States in the early 1930s. It was a braced high-wing monoplane with conventional tailwheel landing gear with a fully enclosed cabin, superficially resembling the Travel Air 10. At the time of the CW-15's design, Travel Air had recently been acquired by Curtiss-Wright.
The Fairchild Model 45 was a 1930s American five-seat cabin monoplane aircraft designed and built by Fairchild.
The Macchi M.C.94 was a 1930s Italian commercial flying boat built by Macchi.
The Focke-Wulf A 20 Habicht was an airliner developed in Germany in the late 1920s. It was a high-wing cantilever monoplane with fixed tailskid undercarriage. The fuselage was deep and seated four passengers in a fully enclosed cabin. The type was not bought by the airlines and only a few examples were built.
The PWS-21 was a Polish passenger aircraft for 4 passengers, built in PWS factory in 1930, that remained a prototype.
The Nord 3400 Norbarbe was a French two-seat observation and casualty-evacuation aircraft built by Nord Aviation for the French Army Light Aviation.
The Lublin R-XI was the Polish passenger plane for 4 passengers, designed in 1930 in the Plage i Laśkiewicz factory in Lublin, that remained a prototype.
The Bayerische Flugzeugwerke M 18, was an airliner, produced in Germany in the late 1920s.
The SECAN SUC-10 Courlis was a French high-wing touring monoplane designed and built by Société d'Etudes et de Construction Aéronavales (SECAN), a branch of the automobile company Société des Usines Chaussons. The aircraft had problems with the engine installation and only 144 were built, some without engines and were scrapped.
The Spartan C4 was an American four-seat cabin monoplane designed and built by the Spartan Aircraft Company.
The Dornier Do K was a German commercial passenger and freight monoplane, designed by Claude Dornier and built by Dornier Flugzeugwerke. Only three prototypes of different designs were built and the type was not a commercial success.
The PWS-11 was a Polish aerobatic and trainer aircraft, developed in 1928-1929 by PWS, which remained a prototype.
The Thaden T-4 Argonaut was a 1930s American four-seat all-metal cabin monoplane built by the Thaden Metal Aircraft Company of San Francisco, California.
The Supermarine Type 179 "Giant" was a British monoplane flying boat developed by Supermarine but cancelled before completion.
The SIPA S.70 was a late 1940s French eight-passenger light transport aircraft prototype built by Société Industrielle Pour l’Aéronautique (SIPA).
The Morane-Saulnier MS-700 Pétrel was a French four-seat cabin-monoplane designed and built by Morane-Saulnier, only three prototypes were built.
The Caproni Ca.131 was a prototype for a large aircraft built in Italy in 1934, intended for use as either a bomber or airliner. It was a conventional low-wing cantilever monoplane, powered by a radial engine on each wing and in the nose. The main undercarriage was housed within large streamlined spats. Configured as an airliner, it would have seated 17 passengers.
