The C-47 was a military adaptation of the Douglas DC-3, a twin-engine low-wing monoplane with retractable landing gear that quickly dominated the infant commercial airline industry from its first appearance in 1935. With war clouds gathering over Europe, the Army Air Forces ordered military versions of the DC-3 in 1939, and the first of these, the C-53 Skytrooper, entered production in October 1941. The C-53 Skytrooper was developed as a dedicated troop transporter and for dropping paratroops. It was very similar to the C-47 Skytrain, but without the reinforced cargo floor, large cargo door and hoist attachment of the dual purpose C-47. In all, some 250 C-53s were produced.