The Boeing C-97 Stratofreighter was a long range heavy military cargo aircraft based on the B-29 bomber. Design work began in 1942, with the prototype's first flight in 1944, and the production aircraft entering service in 1947. Between 1947 and 1958, 888 C-97s in several variants were built - 816 of them KC-97 tankers. C-97s served in the Berlin Airlift, the Korean War, and the Vietnam War. Some aircraft served as flying command posts for the Strategic Air Command, while others were modified for use in Aerospace Rescue and Recovery Squadrons (ARRS).
The Boeing C-97 Stratofreighter was developed towards the end of World War II by fitting an enlarged upper fuselage onto a lower fuselage and wings which were essentially the same as the B-50 Superfortress with the tail, wing, and engine layout being nearly identical. It was built before the death of Boeing president, Philip G. Johnson.
The prototype XC-97 was powered by the 2,200&_160;hp (1,640&_160;kW) Wright R-3350 engine, and was fitted with a built-in ramp and a hoist to help in the loading and unloading of supplies and personnel through the large clamshell-type doors in the belly. On January 9, 1945 the first prototype, piloted by Major Curtin L. Reinhardt, flew from Seattle to Washington, DC in 6&_160;hours 4&_160;minutes, an average speed of 383&_160;mph (616&_160;km/h) with 20,000&_160;pounds (lb) of cargo, which was for its time rather impressive for such a large aircraft. Production models featured the 3500&_160;hp (2,610&_160;kW) Pratt & Whitney Wasp Major engine, the same engine as the B-50.
The C-97 had a useful payload of 35,000&_160;lb (16&_160;t) and could carry two normal trucks or light tanks. The C-97 was also the first mass produced air transport to feature cabin pressurization, which made long range missions somewhat more comfortable for the crew and passengers.