Boeing 707 ushering in the Jet Age. It established Boeing as one of the largest manufacturers of passenger aircraft, and led to the later series of airliners with "7x7" designations. The later 720, 727, 737, and 757 share elements of the 707's fuselage design. The 707 was developed from the Boeing 367-80, a prototype jet first flown in 1954. A larger fuselage cross-section and other modifications resulted in the initial-production 707-120, powered by Pratt & Whitney JT3C turbojet engines, which first flew on December 20, 1957. Pan American World Airways began regular 707 service on October 26, 1958. Later derivatives included the
Boeing 707 707 would be profitable was far from certain. At the time, Boeing was making nearly all of its money from military contracts: Its last passenger transport, the Boeing 377 Stratocruiser, had netted the company a $15 million loss before it was purchased by the Air Force as the KC-97 Stratofreighter. In a demonstration flight over Lake Washington outside Seattle, on August 7, 1955, test pilot Tex Johnston performed a barrel roll in the 367-80 prototype. The 132-inch (3.35 m) wide fuselage of the Dash 80 was large enough for four-abreast (two-plus-two) seating like the Stratocruiser. Answering customers' demands and under