Talking of aerobatics, we once - and only once, sadly - saw a flycatcher in our garden (a spotted flycatcher, IIRC). We were sitting out the back one evening and saw this small brown bird (unremarkable in appearance) doing these amazing aerobatic stunts and then landing on the fence. Then off it would go again. Not having seen one before (or since!) we didn't know what it was at first, but then we realised it was catching insects and worked it out.