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 also smaller and slower than the 707. Several major airlines committed only to the (second place in the production race) Douglas DC-8. Douglas Aircraft was the more established and preferred (by airlines and their passengers) maker of passenger aircraft at the time. Douglas had correctly decided to await the validation of a larger and more fuel efficient engine (JT4A from Pratt & Whitney), and to design a larger and longer range aircraft around this engine. To stay competitive, Boeing made a late and costly decision to redesign and enlarge the 707's wing to help increase range and payload. The new