Boeing B-29 airplane model. The first service test airplane was first flown on June 26, 1943, and deliveries of the aircraft began almost immediately. While itself one of the most innovative airplanes in aviation history, the B-29 also played a part in supersonic research, used as a launch platform for dropping rocket-powered research airplanes. The production total of nearly 4,000 B-29s of all versions must be regarded as very large, having regard to their size and cost, and it is not surprising that B-29s saw a wide variety of employment following World War II, operating under several designations. A number of B-29s were used operationally during the Korean War.