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
El Al ("Starting Dec. 23, the Atlantic Ocean will be 20% smaller") to promote its non-stop transatlantic flights. This was a bold step: the airline industry had never used images of the ocean in its advertising because of the widespread public fear of airline crashes. The advertisement, which ran only once, proved effective. Within a year, El Al's sales tripled. Despite the purchase of its Britannias and inauguration of non-stop transatlantic flights the airline remained unprofitable. When Efraim Ben-Arzi took over the company in the late 1950s, the Britannias were replaced in the next decade by the Boeing 707 and Boeing 720