Background Information.

During and after World War II, Boeing was known for its military aircraft. The company had produced innovative and important bombers, from the B-17 Flying Fortress, the B-29 Superfortress to the jet-powered B-47 Stratojet and the B-52 Stratofortress. The company's civil aviation department lagged far behind Douglas and other competitors, its only noteworthy airliners being the Boeing 314 Clipper and the Boeing 307 Stratoliner.

During 1949 and 1950 Boeing embarked on studies for a new jet transport, realizing that any design must be aimed at both military and civilian markets. Aerial refuelling was becoming a standard technique for military aircraft, with over 800 Boeing KC-97 Stratofreighters on order from the United States Air Force. With the advent of the jet age a new tanker was required to meet the USAF's fleet of jet-powered bombers, this was where Boeing's new design would win military orders.

Boeing studied numerous wing and engine layouts for its new transport/tanker, some of which were based on the B-47 and C-97, before settling on the ‘367-80’ prototype aircraft.

The ‘Dash 80’ took less than two years from project launch in 1952 to rollout on May 14, 1954. First flight took place on July 15, 1954. It was powered by the Pratt & Whitney JT3C turbojet engine, the civilian version of the J57 as used on many military aircraft, including the F-100 Super Sabre fighter and the B-52 bomber. The prototype was a proof-of-concept aircraft for both military and civilian use. The United States Air Force was the first customer, using it as the basis for the KC-135 Stratotanker aerial refuelling aircraft.

Whether the passenger 707 would be profitable was far from certain. At the time, nearly all of Boeing's revenue came from military contracts. Its last passenger aircraft, 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 07, 1955, test pilot Tex Johnston performed a barrel roll in the 367-80 prototype. Although he justified his unauthorized action to Bill Allen, the president of Boeing, as selling the airplane with a 1 'g' manoeuvre he was told not to do it again.

The 132 in (3,352.80 mm) wide fuselage of the ‘Dash 80’ was large enough for four-abreast (two-plus-two) seating like the Stratocruiser. Answering customers' demands and under Douglas competition, Boeing soon realized this would not provide a viable payload, so it widened the fuselage to 144 in (3,660 mm) to allow five-abreast seating and use of the KC-135's tooling. Douglas Aircraft had launched its DC-8 with a fuselage width of 147 in (3,730 mm). The airlines liked the extra space and six-abreast seating, so Boeing increased the 707's width again to compete, this time to 148 in (3,760 mm).

Although it was not the first commercial jetliner in service, the Boeing 707 was the first to be widespread and is often credited with beginning the ‘jet age’. It dominated passenger air transport in the 1960s and remained common through the 1970s, on domestic, transcontinental and international flights, as well as cargo and military applications. It established Boeing as a dominant airliner manufacturer for many a year to come - as this fuselage cross-section allowed six-abreast economy seating, that was retained in the later 720, 727, 737 and 757 airliners.

The initial 145-foot-long (44 m) 707-120 was powered by Pratt & Whitney JT3C turbojet engines. The shortened long-range 707-138, built only for Qantas Airways, and the more powerful 707-220 entered service in 1959. The longer range, heavier 707-300/400 series have a larger wing and stretched slightly by 8 feet (2.4 m). Powered by Pratt & Whitney JT4A turbojets, the 707-320 entered service in 1959, and the 707-420 with Rolls-Royce Conway turbofans in 1960.

The Boeing 720, a lighter short-range variant, was also introduced in 1960. Powered by Pratt & Whitney JT3D turbofan engines, the 707-120B debuted in 1961 and the 707-320B in 1962. The 707-120B typically flew 137 passengers in two classes over 3,600 nmi (6,700 km), and could accommodate 174 in one class. With 141 passengers in two classes, the 707-320/420 could fly 3,750 nm (6,940 km) and the 707-320B up to 5,000 nmi (9,300 km). The 707-320C convertible passenger-freighter model entered service in 1963, and passenger 707s have been converted to freighter configurations. Its military derivatives include the E-3 Sentry airborne reconnaissance aircraft and the C-137 Stratoliner VIP transport.

A total of 865 Boeing 707s were produced and delivered, not including 154 Boeing 720s.