After the ban was lifted this company became the Oszkár Asboth Aircraft Factory and began manufacturing in Budapest their patent light wooden car bodies, aeroplanes and propellers.

In 1928, Asboth followed up the earlier experimental work on vertical take-off aircraft, carried out during World War I by Petróczy, Kármán and Zurovec.

The original prototypes carried a car for an observer and allowed rapid vertical flight using tethering cables to hold them in position and aid stability.

Over the two years of experimentation the two large wooden propellers - positioned one above the other and rotating in opposite directions - managed to raise Asboth's device into the air together with its pilot more than 250 times and for periods of almost one hour.

[1] But because of their rigid propellers Asboth's "helicopters" became unstable when moving forward or when subjected to a strong side wind.

[3] In 1941, he left Germany and returned to Hungary, where he experimented on boats powered by aircraft propellers and contributed to scientific journals.