A unique design, the Saab 21 is a very rare find these days, with only three complete examples left. Designed with a push-propeller, it was equipped with a jet engine in 1947, becoming the first Swedish fighter jet. Serial 21311 was delivered with a push-propeller to the Swedish Air Force in 1948.

A lot can be said for the F15 Flygmuseum at Söderhamn. Although somewhat crowded as this photo shows, the museum has creadted dioramas that clearly show unique features either with the aircraft or the unit. In this case, with the long-legged push-propellor J 21, they illurstrate the early adoption of ejector seats on the type. The first test of the seat developed by Bofors took place in 1943 with the first ejection from flight took place in July 1946. The aircraft carries the colours of 1. Divisionen of F15 Hälsinge flygflottilj which was based at Söderhamn.