The Mig-21 was originally built by the Mikoyan and Gurevich Design Bureau in the Soviet Union with a NATO nickname Fishbed. No other jet has had as many planes produced as the Mig-21. Depending on the reference source 8,000 - 13,000 planes of all versions were made in the Soviet Union, under license to allied countries and China without license. A small, fast, agile, dependable and most importantly simple making it easy to turn out great numbers of the plane.
The MiG-21PFM was one variant of the popular MiG-21 with 944 MiG-21PFS/PFM variants being produced. The MiG-21PFM (NATO FISHBED-F) entered service in 1966 as a modified variant of the MiG-21PF. Among the upgrades were new radars, IFF transponder, better avionics and a 23mm cannon that was added due to experience with earlier variants in Vietnam. MiG-21PFM aircraft manufactured after 1968 were capable of carrying Kh-66 beam-riding air-to-surface missiles. One variant or another of the MiG-21 served with about 37 countries.