 It was slightly smaller than the M 20, seating only eight passengers instead of the ten that could be carried by the previous aircraft.Two prototypes were initially built with BMW and Junkers inline engines, followed by two more with BMW-built Pratt & Whitney radials.However, Messerschmitt proved unable to sell the design, possibly due at least in part to the enmity of Deutsche Luft Hansa director Erhard Milch towards Messerschmitt.