The 707's jet speed, long range, high seating capacity and operating economics revolutionised airliner travel when it was introduced into service in 1958. The 707 also laid the foundations for Boeing's dominance of the jet airliner market.
Recognising the jet engine's potential for commercial aviation, Boeing (at great financial risk) decided to develop a jet powered transport that could fulfil military tanker transport roles but be easily adapted to become an airliner. The resulting prototype, known as the 367 Dash 80, flew for the first time on July 16 1954. Impressed, the US Air Force ordered a larger version, with a wider fuselage (12 ft, vs 11 ft for the Dash 80) into production as the KC-135 tanker/transport (more than 800 were built). At first, Boeing wanted to sell the same size aircraft to the airlines, but the airlines insisted on an even larger airplane, which Douglas promised to build (this became the DC-8). Boeing finally relented, designing the 707 as a longer aircraft with a slightly wider fuselage (12 ft 4 in).