The KC-135 was born out of necessity and innovation. In the early 1950s, Strategic Air Command was beginning to operate the new jet-powered Boeing B-52 Stratofortress that with in-flight refueling was capable of striking targets anywhere in the world. At the time, however, the only tankers in the SAC inventory were piston-engined KC-97s. The difference in performance between the two planes forced the B-52 to fly near its aerodynamic stall speed during aerial refueling. This situation created an opportunity for Boeing to introduce a jet-powered aerial refueling tanker—and further refine the “flying boom” refueling technology it invented in the late 1940s.