Sukhoi Su-15 (NATO designation: Flagon) was developed in the 1950s, in response to the US B-52 threat. It was born to replace the main Soviet interceptor fighter at that time, the Su-11 Fishpot-C. The Sukhoi Su-15 made its first flight in 1962, and entered service in 1965, with a total of more than 1,200 built. Like other national treasures, they were not exported.