The SIAI Marchetti S.M. 75 was a civilian transport and was very successful commercially and was designed by Alessandro Marchetti. The design eventually led to the Savoia-Marchetti SM.79 bomber.
The S.M. 75 was made from a composite structure and covering.
The passenger cabin had heating and ventilation.
When World War II broke out the Italian Air Force took over the civilian aircraft.
Some of the transports were used as bombers.
Some of the S.M. 75s survived World War II and remained in use until 1949.