Boeing C - 97 Stratofreighter 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 being on 9 November 1944 , and the first production aircraft entered service in 1947 . Between 1947 and 1958 , 888 C - 97s in several versions were built , 816 being 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 ) . Design and development . The 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 those of the B - 50 Superfortress with the tail , wing , and engine layout being nearly identical . It was built before the death of president of Boeing , Philip G . Johnson . It can be easily distinguished from the 377 Stratocruiser by the " beak " radome beneath the nose and by the flying boom and jet engines on later tanker models . The prototype XC - 97 was powered by the Wright R - 3350 engine , the same as used in the B - 29 . This aircraft and the other pre - production examples were fitted with a shorter fin and rudder than used subsequently . The C - 97 had clamshell doors under its tail , so a retractable ramp could be used to drive in cargo . But unlike the later Lockheed C - 130 Hercules , it was not designed as a combat transport which could deliver directly to primitive forward bases using relatively short takeoffs and landings . The rear ramp could not be used in flight for air drops . On 9 January 1945 , the first prototype , piloted by Major Curtin L . Reinhardt , flew from Seattle to Washington , DC in 6 hours 4 minutes , an average speed of with of cargo , which was for its time rather impressive for such a large aircraft . Production models featured the Pratt & Whitney Wasp Major engine , the same engine as for the B - 50 . The C - 97 had a useful payload of and could carry two normal trucks , towed artillery , or light tracked vehicles such as the M56 Scorpion . The C - 97 was also the first mass - produced air transport to feature cabin pressurization , which made long range missions somewhat more comfortable for its crew and passengers . Operational history . One YC - 97A ( 45 - 9595 ) was used in the Berlin Airlift during April 1949 operating for the 1st Strategic Support Squadron . It suffered a landing gear accident at Rhein Main Air Base and by the time it was repaired , the Soviet Blockade was lifted . C - 97s evacuated casualties during the Korean War . C - 97s also participated in the Biafran airlift , delivering relief materials to Uli airstrip in Biafra during the Nigerian Civil War . Flying under the cover of darkness and at treetop level to evade radar , at least two C - 97s were lost . The USAF Strategic Air Command operated C - 97 Stratofreighters from 1949 through 1978 . Early in its service life , it served as an airborne alternative SAC command post . While only 60 C - 97 transports were built , 816 were built as KC - 97 Stratotankers for inflight refueling . The civilian derivative of the C - 97 was the Boeing 377 Stratocruiser , a very luxurious transoceanic air liner which featured a lower deck lounge and could be fitted with sleeper cabins . Two C - 97s are still airworthy at the present day , one ( s / n 52 - 2718 , named " Angel of Deliverance " ) operated as a privately owned warbird , the other operated as a fire bomber in the United States . The Israelis turned to Stratocruisers and KC - 97s when they could not buy the highly regarded C - 130 . The Israelis adapted Boeing 377 Stratocruiser airliners into transports , including many using C - 97 tail sections including the loading ramp . Others were adapted with swiveling tails and refueling pods . One Israeli C - 97 was downed by an Egyptian SA - 2 Guideline missile on 17 September 1971 , while flying as an electronic counter - measures platform some 12 miles from the Suez Canal . Operators . USAF Units . The following USAF wing organizations flew the various C - 97 models at some time during their existence :