Martin B-57B Canberra After the Korean War began in 1950, the U.S. Air Force looked for a jet-powered medium bomber to quickly replace the aging, propeller-driven Douglas B-26 Invader. In March 1951 the USAF contracted with Martin to build the British Canberra in the United States under license. The Martin-built B-57 made its first flight in July 1953, and when production ended in 1959, a total of 403 Canberras had been produced for the USAF. In 1965 the USAF sent two B-57B squadrons to South Vi