In 1937, Dornier obtained a patent for a plane with two engines in the fuselage, driving the pull and push propellers. The design was marked P.59, and its concepts were refined in 1939 in the P.59-05 variant, after which the design was put in a drawer. This type of plane was not needed at the time. Nevertheless, limited experimental work was carried out, the result of which was a small Goppingen Go-9 plane, with an aerodynamic system obtained from P.59, as well as three-support landing gear with a front wheel and an engine driving a push propeller through a long shaft. The results of these experiments were used when designing the P.231 aircraft in several variants - also combining piston and jet propulsion. When in 1942 the RLM announced the requirements for a high-speed multipurpose aircraft, the equivalent of the British Mosquito, Dornier proposed the P.231 as a rather unusual answer. Despite the risks posed by the different P.231 concept, Dornier was commissioned to build several prototypes.

The Focke-Wulf Ta 154 Moskito was a fast twin-engined German night fighter aircraft. The German Ta 154 night fighter which supposed to be an answer to the British Mosquito.

In 1936 the D-513 fighter designed by Emil Dewoitine made its first flight. It was supposed to be the successor of the slightly outdated D-500 and D-510 models, and built according to modern trends: with a closed cabin and a retractable undercarriage. Unfortunately, the tests turned out to be very disappointing. At the same time, as a result of the nationalization of the aviation industry, Dewoitine's industries were absorbed by the SNCAM. Dewoitine, however, did not give up on the project and, in cooperation with his engineers, developed a new model - the D-520.