What I would do is, go down there, slowly and listen. If you hear it, try to isolate where the sound is coming from. The first thing you need to be able to do is identify what kind of flying... whatever... it is. Move slowly and quietly. *IF* a bee, wasp, etc. does land on you... STAY STILL! They only sting when they are frightened or feel threatened. If you go flailing around, you're going to freak it out and it will do whatever it needs to do to defend its self. Granted, standing still and choking back the urge to swat at it and run away isn't easy, but it will help you to be able to avoid getting stung.

If you need to feed your gliders, try to get them fed. If you don't see or hear the little bugger, go about your business, if you do, let the gliders wait until you are able to remove the bug.

Have your ceiling checked. If it's a bee, wasp or hornet, they are not solitary insects.