It was a jet-powered development of the piston-engined Saab 21 which, along with the Russian Yakovlev Yak-15, was one of only two jet fighters to have been successfully converted from a piston-powered aircraft.
It was a jet-powered development of the piston-engined Saab 21 to have been successfully converted from a piston-powered aircraft. This Saab 21-15, was one of only two jet fighters. This was along with the Russian Yakovlev Yak.