By what two-word name was the Boeing B-17 aircraft known?
Boeing B-17 Flying Fortress NAN10-50.jpg|thumb|B-17 modified for testing of the [[Pratt & Whitney T34|XT-34 turboprop]]. When testing concluded, the aircraft was restored to stock configuration as the "[[Liberty Belle (B-17)|Liberty Belle]]", but was lost in a post-forced-landing fire near [[Oswego, Illinois]] on 13 June 2011.]] [[Category:Boeing aircraft|B-17 Flying Fortress]] [[Category:United States bomber aircraft 1930–1939]] [[Category:Four-engined tractor aircraft]] [[Category:Low-wing aircraft]] [[Category:World War II bombers of the United States]] [[Category:Boeing B-17 Flying Fortress| ]] [[Category:Aircraft first flown in 1935]] Boeing B-17 Flying Fortress The Boeing B-17 Flying Fortress is a four-engined heavy bomber developed in the 1930s for the United States Army Air Corps (USAAC). Competing
Boeing B-29 Superfortress total was 3,970 aircraft. Dozens of B-29s remain as static displays, but only two examples, "Fifi" and "Doc", have been restored to flying status, with "Doc" flying again for the first time from McConnell AFB on July 17, 2016. A transport developed from the B-29 was the Boeing C-97 Stratofreighter, first flown in 1944, followed by its commercial airliner variant, the Boeing Model 377 Stratocruiser in 1947. This bomber-to-airliner derivation was similar to the B-17/Model 307 evolution. In 1948 Boeing introduced a tanker variant of the B-29 as the KB-29, followed by the Model 377-derivative KC-97 introduced in 1950. A