Mig-21 Fishbed / NVAFMig 21 Fishbed North Vietnam model airplane. During the Vietnam War, NVAF MiG 21s were often used against U. S. aircraft. Between April 26, 1965 and January 8, 1973, USAF F 4s and B 52s downed 68 MiG 21s. More than 30 countries of the world including nations friendly to the U. S. have flown the MiG 21. At least 15 versions of the MiG 21 have been produced, some outside the Soviet Union. Estimates place the number built at more than 8,000, a production