I absolutely 100% agree with Deja's statement.
It is really hard to say where the line between pilot and plane skill begins/ends (or indeed if there even is a line). For example, Frenchy in a P47 is a terrible sight to behold (unless you are his wingman, then it is pretty damn neat). However, every time I've fought him when he was NOT in a P-47 I think I've won. (I think, I could be wrong here). He can fling that plane around like nobody I've ever seen though.
In some cases I think the plane makes the difference though. For instance, when you are in a situation where your plane does NOTHING better than the plane you are fighting, your only solution is to not 'fight' at all. This strategy was used historically, and successfully, by F4F pilots early in the Pacific War. The Zero was better at EVERYTHING (yea, it was even faster, believe it or not).
Same sort of thing in AH, if I am in a G10 or a D9, I just HATE seeing La-7s. In the earlier models I don't hate seeing them as much, because at least the early models can turn somewhat better (well, not the 190s). But in AH, the La-7 does everything better than a G10. You can't turn, you can't dive, you can't climb, and you can't run. So I'd say if you take a pilot that I could kill in a 109 (if we were both flying G-10s), and put him in an La-7, you just drastically increased his chances of winning the fight.
But in most cases I agree, it is definately the pilot, and not the plane.