In 1941 the Army Air Forces selected a modified version of the DC-3 -- the C-47 Skytrain -- to become its standard transport aircraft. The C-47 could carry up to 6,000 pounds of cargo and could hold a fully assembled jeep or a 37 mm cannon. It could carry 28 soldiers in full combat gear or 14 stretcher patients and three nurses as a medical airlift plane. Seven basic versions were built, and the aircraft was given at least 22 designations. C-47s remained in active military service long after the end of World War II. They played a critical role in the 1948 Berlin Airlift and saw action in the Korean and Vietnam wars.