C-54 SkymasterDouglas C 54 Skymaster airplane model. The Douglas C 54 Skymaster, a four engine transport aircraft, was utilized by the United States Army Air Forces during World War II. Similar to the C 47 Skytrain, it was adapted from the civilian Douglas DC 4 airliner. The C 54s entered service in 1942, initially carrying up to 26 passengers, with later models accommodating up to 50 passengers. The U. S. Navy also operated this aircraft, designating it as R5D. It