The Boeing B-29 Superfortress is a four-engine https://en.wikipedia.org/wiki/Fixed-wing_aircraft#Propeller_ https://en.wikipedia.org/wiki/Heavy_bomber designed by https://en.wikipedia.org/wiki/Boeing which was flown primarily by the https://en.wikipedia.org/wiki/United_States during https://en.wikipedia.org/wiki/World_War_II and the https://en.wikipedia.org/wiki/Korean_War . It was one of the largest aircraft operational during World War II and featured https://en.wikipedia.org/wiki/State_of_the_art technology.