The 357th Fighter Group was an air combat unit of the United States Army Air Forces during the Second World War. The 357th operated P-51 Mustang aircraft as part of the U.S. Eighth Air Force and its members were known unofficially as the Yoxford Boys after the village of Yoxford near their base in the UK. Its victory totals in air-to-air combat are the most of any P-51 group in the Eighth Air Force and third among all groups fighting in Europe.

The North American Aviation P-51 Mustang is an American long-range, single-seat fighter and fighter-bomber used during World War II and the Korean War, among other conflicts. The Mustang was designed in April 1940 by a team headed by James H. Kindelberger of North American Aviation (NAA) in response to a requirement of the British Purchasing Commission. The commission approached NAA to build Curtiss P-40 fighters under license for the Royal Air Force (RAF). Rather than build an old design from another company, NAA proposed the design and production of a more modern fighter. The prototype NA-73X airframe was rolled out on 9 September 1940, 102 days after the contract was signed, and first flew on 26 October.