The Douglas C-47 Skytrain is a military transport aircraft that was developed from the Douglas DC-3 airliner. The Douglas Aircraft Company first flew its plane on 23 December 1941, and it was used by the US Air Force, Royal Air Force, US Navy, and the Royal Canadian Air Force, among other Allied Powers nations, during World War II. 10,174 C-47 Skytrains were built by the United States, and they were used as troop transports, also taking part in paratrooper drops. By 2017, the plane was still in use with the armies of Colombia, Greece, El Salvador, and South Africa.