The Do-31 was the only VTOL transport aircraft with jet engines ever built. Two prototypes were used between 1967-1969 as experimental aircraft for researching and testing but the project was cancelled in 1970. This aircraft was initially put into storage at Oberpfaffenhofen, then went for several years on display in the open in the courtyard of the Deutsches Museum in Munich. After restoration it is now on display at the Deutsches Museum - Flugwerft Schleissheim.