Boeing 707 center section tanks. Its first flight was on January 11, 1958; 69 turbojet 707-320s were delivered through January 1963, the first passengers being carried (by Pan Am) in August 1959. The 707-420 was identical to the −320, but fitted with Rolls-Royce Conway 508 (RCo.12) turbofans (or by-pass turbojets as Rolls-Royce called them) of 18,000 lb (79 kN) thrust each. The first announced customer was Lufthansa. BOAC's controversial order was announced six months later, but the British carrier got the first service-ready aircraft off the production line. The British Air Registration Board refused to give the aircraft a certificate of airworthiness,
Boeing 367-80 707 fuselage with that width. By the time the Boeing company committed to production, the decision had been made to design the production model 707 as a six-abreast design, with a larger diameter fuselage, after C.R. Smith, CEO of American Airlines, told Boeing he wouldn't buy the 707 unless it was an inch wider than the then-proposed Douglas DC-8 passenger jet. This decision did not unduly delay introduction of the production model since the -80 had been largely hand-built, using little production tooling. By early 1952 the designs were complete and in April the Boeing board approved the program. Construction