The P-47 Thunderbolt, built by Republic Aircraft, was one of the mainstay fighters of the US Army Air Corps (formerly the USAF) in the mid-to-late stages of World War II, and was the largest single-engine fighter of its time. Apart from being slightly underpowered at low and medium altitudes, the P-47's huge engines and 3.65 metre diameter propellers allowed it to carry more anti-aircraft firepower, heavier armour and more small bombs for ground attack missions; although its huge fuel consumption shortened its time and range, its total production of 15,686 aircraft made the P-47 The P-47 is the most produced U.S. warplane, with 12,602 D-models, the world's largest production run of a single type of military aircraft. In addition to the US Army Air Forces, other allied air forces also used P-47s. The P-47 was nicknamed the "Jug" by aircrews at the time because of its significantly larger fuselage.