Affectionately known as the 'Jug', the Republic P-47 Thunderbolt was the U.S.'s most widely produced fighter, serving in both the European and Pacific theaters in a variety of roles including air superiority, bomber escort and ground-support. Designed by Alexander Kartveli, the P-47 was born out of the necessity for a heavy fighter suitable to the conditions of modern air combat to which earlier single-engined U.S. fighters like the P-39 and P-40 were woefully inadequate. The most prominent features of the P-47 are the semi-elliptical wing as well as the huge radial engine, a Pratt & Whitney Double Wasp that would also be used in the Corsair and Hellcat. The engine was fitted with an exhaust-driven turbocharger giving the P-47 speed in excess of 400 mph despite its weight; at nearly 8 tons fully loaded it was the heaviest single-engined fighter of its day. The P-47 also packed a considerable punch in the form of four 0.50-in machine guns as well as a considerable bomb and rocket load which along with its ruggedness, made it a formidable fighter-bomber. When introduced in Europe in late 1942 it was the first USAAF fighter to match its Luftwaffe rivals, particularly at high-altitude. It was gradually replaced by the P-51 Mustang for air combat duties yet found new life as an excellent ground-attack fighter where it was, along with the RAF Typhoon, the most important Allied aircraft of this type. Improved and longer-ranged versions were introduced later in the war in both theaters and it also featured prominently in the expeditionary squadrons sent by Brazil to Italy and Mexico to the Philippines while also in use by French, Soviet, and British forces via Lend-Lease, the latter which used it extensively in South-East Asia. The top P-47 ace was 'Gabby' Gabreski (34.5 kills) of the 56th Fighter Group, the only unit in Europe to fly the P-47 in the fighter role until the end of the war.

The Thunderbolt was first flown on 6 May 1941 as the XP-47B for the requirement of (most ironically) a lightweight fighter. The P-47B entered service in mid-1942 and began flying combat missions in Europe in the spring of 1943, escorting B-17 formations and performing fighter sweeps on occupied territory. Many of its faults were corrected in the P-47C which saw combat shortly after, nevertheless the most popular variant of the 'Jug' was the P-47D which came in an early 'Razorback' version and then a 'Bubble-top' version which was first introduced in the P-47D-25 block. This new canopy gave the pilot improved all-around vision and other smaller changes gave the aircraft slightly more range though it somewhat strange that a new designation was not applied. In fact, the P-47D was the most produced aircraft sub-variant in US history with over 12,000 built. Final P-47 variants attempted to squeeze as much juice from the basic design, this began with the P-47M which was a faster pure-fighter version designed for the European theater which met with some success against Me 262 jet fighters. On the other hand, the P-47N was adapted to Pacific requirements which included a redesigned wing for much greater range to escort B-29 heavy bombers as well as for attack missions in China, Korea and Japan itself. P-47Ds were also used by the USSR, Brazil, Mexico, France and Britain (where it was known as the Thunderbolt Mk. I) during the war.