The official record for fastest piston-engined aeroplane in level flight was held by a
Grumman F8F Bearcat, the
Rare Bear, with a speed of . The unofficial record is held by a British
Hawker Sea Fury at . Both were demilitarised and modified fighters. The fastest stock (original, factory-built) piston-engined aeroplane was unofficially the
Supermarine Spiteful F Mk 16, which "achieved a speed of 494m.p.h. at 28,500ft during official tests at Boscombe Down" in level flight.
