Situated next to Belgrade's main airport is an Air Museum still branded with its Yugoslav identity. As someone who is notorious for rocking up at airports very early (I don't want to be one of those people who has to run for their flight) having those close by gave me something to do to kill time.
The building is visible as you drive into the airport complex. If you face away from the departure terminal the museum is to your forward left, and it's no more than a 5 minute walk.
Around the museum are loads of planes, in various states of repair, and helicopters. This bit is free.
Indoors you pay a small charge and can then ascend into the building to check out the planes in there. These appear to be in better condition. You can leave your luggage with reception. On my visit I was the only one there and the guard, who spoke English, seemed pleased to have me visit.
This is the exhibit they're most proud of. Part of the wing and canopy of a stealth bomber that was shot down in 1999; the only recorded occurrence of this ever happening. As a sign of the war being a distant memory the pilot (not the one listed on the canopy) and the guy who shot him down have met and are now good friends.