KC-97 Stratofreighter
The KC-97 Stratofreighter, a B-29 airframe with an enlarged fuselage and modified for mid-air refueling operations, supported B-47 operations until SAC began replacing it with the KC-135 Stratotanker in 1956. The Stratotanker fleet would be joined by the larger McDonnell Douglas KC-10 “Extender” in 1981 – both of which still fly for the Air Force to this day.