Boeing Commercial Airplanes
Boeing Dash 367-80

The Boeing 367-80, known simply as the Dash 80, is an American quadjet prototype aircraft built by Boeing to demonstrate the advantages of jet propulsion for commercial aviation. It served as basis for the design of the KC-135 tanker and the 707 airliner. The Dash 80 first flew in 1954, less than two years from project launch. Its US$16 million cost (equivalent to $174 million today) was an enormous risk for Boeing, which at the time had no committed customers. Only one example was built, which has been preserved and is currently on public display at the Smithsonian's National Air and Space Museum's Udvar-Hazy Center in Virginia.

By the late 1940s two developments encouraged Boeing to begin considering building a passenger jet. The first was the maiden flight in 1947 of Boeing’s B-47 Stratojet bomber. The second was the maiden flight in 1949 of the world's first jet airliner, the de Havilland Comet. Boeing President Bill Allen led a company delegation to the UK in summer 1950, where they saw the Comet fly at the Farnborough Airshow, and also visited the de Havilland factory at Hatfield, Hertfordshire where the Comets were being built. Boeing felt it had mastered the swept wing and podded engines which it saw as key technologies that would enable it to improve on the Comet.