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 707 redesign to the wing and gear structures. The 707-820 was also cancelled in 1966 in favor of the 747. The militaries of the US and other countries have used the civilian 707 aircraft in a variety of roles, and under different designations. (The 707 and U.S. Air Force's KC-135 were developed in parallel from the Boeing 367–80 prototype.) The Boeing E-3 Sentry is a US military airborne warning and control system (AWACS) aircraft based on the Boeing 707 that provides all-weather surveillance, command, control, and communications. The VC-137C variant of the Stratoliner was a special-purpose design meant to serve as