The little known North American B-45 Tornado was a post-war design which in many ways bridged the gap between piston-engined and jet bombers and was inspired by wartime German types like the Arado Ar 234. The B-45's airframe was a conventional straight wing with a raised cockpit and glazed nose yet it was fitted with four turbojets arranged in two wing mounted nacelles. Still, it was the first jet bomber in the USAF arsenal, the first four-engined jet in the world, and the first to drop bombs at over 500 mph. B-45s ultimately served with the newly created Strategic Air Command where they were sent to Europe as a deterrent while reconnaissance variants were used in the Korean War and also operated with RAF colors in secret clandestine missions over Eastern Europe and the Soviet Union during the 1950s. Bomber variants were finally retired in 1958 as more advanced jets began entering service.

Ordered as early as 1944, the prototype XB-45 first flew on 17 March 1945 with J35 engines which was also fitted on the first batch of production B-45A before they were substituted by J47s. The B-45B had upgraded radar but was not built while the definitive B-45C had a strengthened airframe, water injected engines, and wingtip fuel tanks. Reconanissance variants included the RB-45C while other conversions were the TB-45A target tugs and the DB-45A/C drone director aircraft.