TopGun69 said:
As far as I know, the partisans did not have an air force, but had they won independence from German occupation earlier, they certainly would have used the IK-3 in the newly formed Yugoslav Airforce (communist).
Yugoslav partisans DID HAVE airforce, as one and only partisans in occupied Europe

but IK-3 did not flew in it.
Key Dates:
23 May 1942 First two aircraft acquired
4 June 1942 First combat sorties flown
early Sept 1943 Partisans capture former Italian airfield and it's resident aircraft
22 April 1944 352 Sqn formed by RAF with Yugoslav personnel
16 October 1944 Agreement signed with Soviet Union on providing air support to the NOVJ
December 1944 Soviet instructors begin training of Yugoslav aircrews near Belgrade
5 January 1945 New Yugoslav Air Force (JRV) officially established
28 May 1945 War ends in Yugoslavia
More about Partisan Air Force here :
http://www.aeroflight.co.uk/waf/yugo/yugo-part-home.htm