By 1985, the pair of Boeing 707-based VC-137s used as the Presidential aircraft had been in service for 23 and 13 years respectively, and the USAF began searching for an eventual replacement. The Request for Proposal issued stated that the aircraft to be selected should have at least three engines and an unrefueled range of at least . Both Boeing with its 747 and McDonnell Douglas with the DC-10 were in competition to be selected, with the Boeing entry the eventual winner. The fabrication of the current 747s began during the presidency of Ronald Reagan (1981–1989). Reagan ordered two identical Boeing 747-200Bs to replace the Boeing 707s that he used for transport.