The Boeing 727 is a medium-sized narrow-body three-engine commercial jet aircraft, built and developed by the American company Boeing Commercial Airplanes from 1963 to 1984. The first Boeing 727 left the factory on November 27, 1962. It has the same width of the Boeing 707/720 fuselage, which reduced Boeing's tooling costs and airlines' maintenance costs. It is the best-selling model until the early 1980s, with a total of 1,831 aircraft delivered, when it was replaced by the Boeing 737. At the end of April 2017, four Boeing 727-100s and 83 Boeings remained in active service. 727-200. The design of the 727 was due to an agreement between United Airlines, American Airlines and Eastern Airlines to find a successor to the Boeing 707. United Airlines wanted a plane with four engines for its flights to high altitude airports, American was looking for a twin-engine plane for reasons of efficiency, while Eastern wanted a trimotor for its flights over the Caribbean Sea. Finally, the three airlines agreed on a triengine and the 727 was born.