Based on the C-97 (which itself was based on the B-29 bomber), the Boeing KC-97 Stratotanker was the first major strategic tanker aircraft in the world. The KC-97 owed its creation to the development of a practical inflight refuelling boom by Boeing which made such an aircraft feasable. As a result, the KC-97 went on to account for the grand majority of units from the Stratofreighter family where they formed the backbone of the USAF's tanker fleet during the 1950s and 60s tasked with the vital duty of refuelling the Strategic Air Command's B-47 jet bombers during their constant around-the-clock missions around Soviet airspace thus giving them true intercontinental capability . USAF KC-97s were eventually phased out in favor of the jet-engined KC-135 (which also ended up taking its name) which began to replace it starting in 1956 (later versions of the KC-97 had auxiliary turbojets to increase performance relative to the jet aircraft they refuelled). They were finally retired from reserve and ANG units in 1978.

The prototype XC-97 first flew on 11 November 1944 and was basically a B-29 with an enlarged upper fuselage but retaining the lower fuselage and wings. The basic C-97 Stratofreighter was used in limited numbers by the USAF with the gran majority of units becoming the KC-97 Stratotanker. These began with the KC-97A conversions of C-97 units followed by the KC-97E and KC-97F built from the ground as tankers. The KC-97G accounted for well over half of all units and could perform both transport and tanker roles and also featured underwing fuel tanks. Finally, the KC-97L was otherwise similar but aded a pair of turbojet engines for greater thrust. Other versions of the basic C-97 design included the MC-97 air ambulance, the VC-97 airborne command post, EC-97 electronic warfare platform, and the HC-97 for search and rescue (SAR) operations.