I've shot down airjer at 3.8, but he was flying on a path that was straight at me. I just got lucky on guessing the bullet drop. He told me if it had been someone other than me, he would have accused them of using aimbot.

Although not a manned ack, I once killed a P-51 with an osti from 3-4k. I was driving along, looked up & saw the pony flying over me way up there. I took one un-aimed pot shot in his general direction (straight up) just for the heck of it, then drove off about my business. 15 seconds later I get a kill message. It was the pony. The guy asked me on 200 or PM where I was because he never saw me. When I told him I was in an osti waaaayy down here, he started laughing his butt off and congratulating me. Ahh, good times.