MiG-21 Fishbed: The AK-47 of Russian Fighter Jets
The MiG-21 was Mach-2 capable and had a long production run, from 1959 to 1985. Imitation is the sincerest form of flattery, and the MiG-21 Fishbed was updated and modified by companies in India, Israel, and Romania, and the Chinese copied it.
Source: nationalinterest.org