I find planes more annoying than fearsome:
The La-7 and Tempest picker dweebs (or ANY fast picker dweebs) who blow their position and you get around on, so they run out towards friendlies or field ack and wait for you to pull off before reversing on your six. IF YOU'RE GONNA BUG, THEN ***BUG***
262s and 163s. I don't fear them, but I hate seeing them.
Typhoons or Tempests with an altitude advantage, because no matter HOW close to the speed of light they get them, they always seem able to turn on a dime even AFTER I've cleared their guns.
Guys I spot 10K above me. When I'm cruising at FIFTEEN. There's altitude advantages, and then there's just-plain LUDICROUS.