The Boeing Model 307 Stratoliner is an American stressed-skin four-engine low-wing tailwheel monoplane airliner derived from the B-17 Flying Fortress bomber, which entered commercial service in July 1940. It was the first airliner in revenue service with a pressurized cabin, which with supercharged engines, allowed it to cruise above the weather. As such it represented a major advance over contemporaries, with a cruising speed of 220 mph (350 km/h) at 20,000 ft (6,100 m) compared to the Douglas DC-3's 160 mph (260 km/h), at 8,000 ft (2,400 m) then in service. When it entered commercial service it had a crew of five to six, including two pilots, a flight engineer, two flight attendants and an optional navigator, and had a capacity for 33 passengers, which later modifications increased, first to 38, and eventually to 60.

Trans World Airlines (TWA) was a major airline in the United States that operated from 1930 until it was acquired by American Airlines in 2001. It was formed as Transcontinental & Western Air to operate a route from New York City to Los Angeles via St. Louis, Kansas City, and other stops, with Ford Trimotors. With American, United, and Eastern, it was one of the "Big Four" domestic airlines in the United States formed by the Spoils Conference of 1930.