Shooting a kite down w/ tanks main gun is possible, if attacking kite comes in angle shallow enough and turret turn timing is correct. I have killed several in one sortie, when mauling down a base and autogun cut my track. Defenders then came w/o any kind of coordination and mostly very low. M4 has much slower turret than late model T34/85 (T34/76 and early 85 were slooowww...) but turns very rapidly with accelerator, when one track is down.
What I do not get, are those who pick bombers from 5K, shooting all three in formation down one by one, faster than tank normally reloads once. Or M8s 1-pinging heavy tanks from extreme distance. Yes, it's a skill, but in what..?