At the end of the WW II, and in the late forties, Yugoslavia had quite a number of fighter types in service. One squadron of Spitfires MkVc Trop, and one squadron of Hurricanes were incorporated in the newly created Yugoslav Air Force from the RAF, along with three Spitfires Mk IXc left over by the British.
In late 1944 Soviet Union began training two newly formed units of Yugoslav airmen, one on YAK fighters, the other on Il 2 attack aircraft. The units were operational in the closing stages of WW II, in the spring of 1945.
Yugoslavia had at that time both YAK-1, and YAK-3 although the former was more numerous. YAK 9 was received later, as well.
Spitfires and Yaks were compared in mock dog-fights for example during the Sumadija maneuvers in 1949, immediately after the breaking up of relations with the USSR. An accident also occurred when one of the pilots flew into the ground. The Spitfire and the YAK were especially compared regarding the climb and turn radius, the former preferring to fly maneuvers in the horizontal plane, the latter being lighter exploiting the vertical maneuvers.
Due to the lack of spares which hit the air force in late forties, Spitfires were withdrawn first to recon duties, and later scrapped, while YAKs continued a bit longer, being more numerous.
At that time, which is also interesting, Yugoslavia had in service beside Spitfires, Hurricanes and Yaks, also the Me109G, and the domestic S-49A and S-49C (based on pre war IK-3) were delivered to bridge the gap until the jets came from the West in early fifties. In the early 50's came the P-47D Thunderbolt, too, which was the last propeller driven, single engined single seat fighter to serve in the Air Force, mostly as ground attacker.