The A21A-3 was a Swedish fighter-bomber. During World War II, the Royal Swedish Air Force needed a new fighter plane. At that time, Saab designer Fred Wanström proposed the idea of an aircraft with a pusher propeller after studying German and British designs. He believed this would simplify the installation of armaments and ease takeoff and landing. Development began in 1941, but the first production aircraft did not fly until 1945. SAAB named the aircraft "Tvestjärten" ("Earwig"), but the name did not catch on. The A-3 variant appeared in 1947 when the Swedish Air Force needed a new ground-attack aircraft and the B17 and B5 were severely outdated. This modification involved installing mounts for external ordnance and fuel tanks. The A21A-3 remained in service until 1954, when it was replaced by the A21RB and the A29B.

The A21A-3 was introduced in Update 1.95 "Northern Wind". Its design sets it apart from other aircraft, allowing for a powerful armament and good cockpit visibility, although at the cost of engine overheating and overall poor flight performance. For ground attack it has a ballistic computer which is rarely found on props.