The first KC-10s was delivered to the Air Force's Strategic Air Command (SAC) in March 1981 at Barksdale AFB; the 60th and final KC-10 arrived on 29 November 1988. KC-10 'Extenders' have been operated largely in the strategic refueling of large number of tactical aircraft on ferry flights and the refueling of other strategic transport aircraft. There are 59 KC-10 Extenders in service with the USAF as of 2010 stationed primarily at Travis AFB, California, and McGuire AFB, New Jersey.