 Aerial refueling was becoming a standard technique for military aircraft, with over 800 KC-97 Stratofreighters on order.With the advent of the Jet Age, a new tanker was required to meet the USAF's fleet of jet-powered bombers; this was where Boeing's new design that would win military orders.Boeing studied numerous wing and engine layouts for its new transport/tanker, some of which were based on the B-47 and C-97, before settling on the 367-80 quadjet prototype aircraft.