The North American B-45 Tornado was an early American jet-powered bomber designed and manufactured by aircraft company North American Aviation. It has the distinction of being the first operational jet bomber to enter service with the United States Air Force (USAF), as well as the first multiengine jet bomber to be refueled in midair.The B-45 originated from a wartime initiative launched by the U.S. War Department, which sought a company to develop a jet-propelled bomber to equal those being fielded by Nazi Germany, such as the Arado Ar 234. Following a competitive review of the submissions, the War Department issued a contract to North American to develop its NA-130 proposal; on 8 September 1944, work commenced on the assembly of three prototypes. Progress on the program was stalled by post-war cutbacks in defense expenditure, but regained importance due to growing tensions between America and the Soviet Union. On 2 January 1947, North American received a production contract for the bomber designated B-45A, from the USAF. On 24 February 1947, the prototype performed its maiden flight.

Soon after its entry to service on 22 April 1948, B-45 operations were troubled by technical problems, in particular poor engine reliability. The USAF found the plane to be useful during the Korean War performing both conventional bombing and aerial reconnaissance missions. On 4 December 1950, the first successful interception of a jet bomber by a jet fighter occurred when a B-45 was shot down by a Soviet-built MiG-15 inside Chinese airspace. During the early 1950s, forty B-45s were extensively modified so that they could be equipped with nuclear weapons. Improvements were made to their defensive systems and the fuel tankage was expanded to increase their survivability and range.

In its heyday, the B-45 was important to United States defense strategy, performing the strategically-critical deterrence mission for several years during the early 1950s, after which the Tornado was superseded by the larger and more capable Boeing B-47 Stratojet. Both B-45 bombers and reconnaissance RB-45s served in the USAF's Strategic Air Command from 1950 until 1959, when the USAF withdrew the last ones in favor of the Convair B-58 Hustler, an early supersonic bomber. The Tornado was also adopted by the Royal Air Force (RAF) and operated from bases in Britain, where it was used to overfly the Soviet Union on intelligence-related missions. The RAF operated the type until it had introduced its own indigenously-developed jet bomber fleet in the form of the English Electric Canberra.