@Patine These guys mainly
Since Khrushchev got in power from 1955 onwards relations with the USSR improved dramatically and Tito switched back into the Soviet sphere in the early 1960’s, at the height of the Cold War...
45 Mikoyan Gurevich MiG-21F-13 Fishbed C 1962-1980
36 MiG-21PFM Fishbed F 1967-1994
25 MiG-21M Fishbed J 1970- 1996
6 MiG-21MF Fishbed J 1975- 1996
100 MiG-21bis Fishbed L in 1977- (a small number, remain in service with the Serbian Air Force today).
plus several recce and trainer variants of the Mig-21
They also produced 132 homegrown Soko G-2A (N-60) Galeb1965- (some in reserve in Serbia?) and 103 Soko J-21 Jastreb 1968-1996 to replace their American jets.
These were followed by 27 Orao-1 1979-1997 and 50/58 Orao-2 from 1986 onwards (in service with Serbia) in cooperation with Romania and British engines.
In 1984 they started receiving 90 G-4 Super Galebs, still in Serbian service (about 20)
In 1987 they got 14+2 Mig-29, six were shot by Nato in 1999. They have been supplemented by four aircraft from Russia and two from Belarus a couple of years ago.
I should say that after the Warsaw pact invasion of Czechoslovakia in 1968 Yugoslavia and Romania "teamed up" and their relations with the USSR deteriorated again, but it is complicated.