The Douglas DC-3 is a propeller-driven airliner manufactured by Douglas Aircraft Company, which had a lasting effect on the airline industry in the 1930s to 1940s and World War II. It was developed as a larger, improved 14-bed sleeper version of the Douglas DC-2. It is a low-wing metal monoplane with conventional landing gear, powered by two radial piston engines of 1,000–1,200 hp (750–890 kW). Although the DC-3s originally built for civil service had the Wright R-1820 Cyclone, later civilian DC-3s used the Pratt & Whitney R-1830 Twin Wasp engine. The DC-3 has a cruising speed of 207 mph , a capacity of 21 to 32 passengers or 6,000 lbs  of cargo, and a range of 1,500 mi , and can operate from short runways.

Large numbers of DC-3s and surplus C-47s were in commercial use in the United States in the 1940s. In response to proposed changes to the Civil Air Regulations airworthiness requirements that would limit the continuing use of these aircraft, Douglas offered a late-1940s DC-3 conversion to improve takeoff and single-engine performance. This new model, the DC-3S or "Super DC-3", was 39 in.  longer. It allowed 30 passengers to be carried, with increased speed to compete with newer airliners. The rearward shift in the center of gravity led to larger tail surfaces and new outer, swept-back wings. More powerful engines were installed along with shorter, jet ejection-type exhaust stacks. These were either 1,475 hp  Wright R-1820 Cyclones or 1,450 hp  Pratt & Whitney R-2000 Twin Wasps in larger engine nacelles. Minor changes included wheel-well doors, a partially retractable tailwheel, flush rivets, and low-drag antenna. These all contributed to an increased top speed of 250 mph . With over 75% of the original DC-3/C-47 configuration changed, the modified design was virtually a new aircraft. The first DC-3S made its maiden flight on 23 June 1949.