The McDonnell Douglas KC-10 Extender is currently the largest tanker in the world, sharing duties in the USAF with the smaller KC-135. It is based on the DC-10 airliner and thus shares the same general three-engine configuration in addition to an aerial refueling boom in the rear fuselage with a hose-and-drogue system (additional wing-mounted pods were added subsequently). Inflight-refuelling is done via a digital fly-by-wire system and the boom can transfer up to 1,100 gallons per minute; in addition, the Extender is capable of being refuelled itself by other KC-10s or KC-135s thus greatly increasing its range of operations. Overall, the KC-10 greatly expanded the USAF's air-refueling capabilites and has since seen extensive action in conflicts like the Gulf War, Bosnia, Kosovo and the recent wars in Afghanistan and Iraq although perhaps their most memorable action was the inflight-refuelling of UK-based F-111 bombers for strikes against Libya in 1986's Operation El Dorado Canyon.

The USAF's Strategic Air Command received its first converted DC-10s in 1981 and were subsequently designated as the KC-10A. No other variants have been built for the USAF although the Royal Netherlands Air Force uses a similarly-converted version of the DC-10 known as the KDC-10.