Two crew areas, fore and aft, were pressurized and connected by a long tube over the bomb bays, allowing crew members to crawl between them. One of the most technologically advanced airplanes of World War II, the B-29 had many new features, including guns that could be fired by remote control. Boeing submitted the proposal for the B-29 long-range heavy bomber to the Army in 1940, before the United States entered World War II.
