Well, first off let's assume I'm in my "interceptor du jour" - Yak9U - and cruising into the main air travel lanes. I find aircraft co-alt or within a couple of feet of altitude as me. I'll intercept everything, but get particularly frothy about intercepting any of the USN planes, Mustangs, P-38s, 109s, 190s, LA-7s, N1K2s, and Spitfires. Why? Because my Yak9U has proven time and again that it can kill any of these planes. And N1K2s, LA-7s, and Spitfires tend to be flown by pilots who don't really have a good command of the view systems and ACM in general, so after a couple of turns I'll usually be working my way into a firing solution after the initial merge.
N1K2s can be tricky to judge because of the way they can budget their energy states so effectively, but if I can get an LA-7 to turn, I can take'em. And if the LA-7 tries to run away, he'll have to fly fairly straight and level and give me a good d400 tail shot (which is about as far away as a Yak9U can hit effectively). Spitfires can be a bit trickier because of their turn radius, but if I can get behind and below them, eventually I can take'em because the pilot will do something stupid, like reverse his turn or bank so hard that he bleeds his speed, while I'm in his blind spot.
Mustangs can be killed so long as I can stay within range of'em. Once they start to pull away, all I can do is let'em go. Same with the fast 190s and the G10 on WEP. If they turn, I can pop'em. Otherwise I'll just try the d400 sniper shot and hope something falls off, like a rudder or a stabilizer.
A Yak9U carries enough ammo to kill 3 bombers, so long as a majority of the shells hit the target. I usually go for a stabilizer or a wingtip, though last night I was able to detonate quite a few bomber but had nothing but MGs by the time I got to the third one. The downside is that the first thing to get hit by bomber gunners is the radiator, and once that goes the Yak9U engine will crap out in about a minute, maybe less.
If I'm in my other aircraft - my Mustang air patrol cruiser - I'll only engage if the aircraft is below me. Co-alt is no good because it puts me in a bad energy situation. I'll go after USN planes, Spitfires, and N1K2s with much gusto, but will only follow them through one, maybe two, turns and then climb out to set up my next attack run. I'll avoid LA-7s when I'm in a stang and there are other enemy planes around. If I can go into a 1 v 1 fight against an LA-7, I'll engage him and try to work him down into a low-speed turn fight. Sometimes this works, but usually he's on the horn calling for help that always seems to show up just as I'm starting to land shells.
