Designed as a jet powered successor to the legendary P-47 Thunderbolt, the Republic F-84 Thunderjet was the last subsonic straight winged fighter to be used by the USAF. It was nearly cancelled due to numerous structural and engine problems to the point that the aircraft was forced to be used as a fighter-bomber, a role in which it ended up excelling in but only after a series of modifications throughout its service life which greatly expanded its capabilities. Thanks to this, the F-84 distinguished itself in combat during the Korean War where it was initially tasked as escorts for B-29s but later (due to its inferiority versus the MiG-15) became the USAF's primary ground attack aircraft. Later variants known as the F-84 Thunderstreak featured swept wings and were not retired from front-line service until 1964 (reconnaissance units until 1972). F-84s were ultimately used by over a dozen air forces including various NATO nations such as Belgium, Denmark, France, Germany, Greece, Italy, the Netherlands, and Turkey and were also the first aircraft to be used by the USAF's acrobatic display team, the famous Thunderbirds.

First flight of the XP-84 took place on 28 February 1946 and was followed by pre-production the YF-82A. The first service type was the F-82B Thunderjet followed by the F-82C with a new electrical system and a different engine. Both were eventually replaced by the F-84D with various structural modifications and was the first version to be sent to Korea although it was merely an interim type pending the introduction of the F-84E with numerous improvements such as wingtip fuel tanks, a radar gunsight, and a strengthened structure for greater weapons loads. The final Thunderjet variant was the F-84G which was the first fighter to feature inflight refueling systems. The ultimate development of the F-84 family was the F-84F Thunderstreak, very much a new aircraft with swept wings and a more powerful license-built Armstrong Siddeley Sapphire engine. Other sub-variants included the RF-84F Thunderflash tactical reconnaissance platform with nose mounted cameras and engine intakes moved to the wing roots.