The Saab Viggen (Bolt) or Saab 37 is a Swedish fighter aircraft manufactured between 1970 and 1990 to replace the Saab J 35 Draken (Kite or Dragon). The first studies aimed at developing a successor to the Draken were carried out between 1952 and 1957 involving the legendary Finnish aircraft designer Aarne Lakomaa. Construction started in 1964, with a first prototype maiden flight in 1967. The aim was to produce a robust single-engined fighter with excellent STOL performance that could be operated from improvised facilities such as roads and highways in the event of nuclear attacks on major installations. Other requirements included supersonic ability at low level, Mach 2 performance at altitude, and the ability to make short landings at low angles of attack (to avoid damaging improvised runways).