Disagree with the premise.
You are talking as if the Air War didnt develop at all.
Allied fighters will start out with no P-51, only P-38s and P-47s. They have fuel issues as well, where defending fighters can last longer at full power on the defensive near friendly bases.
The LW does get later varients of the 109 and 190 as the war progresses, 109D-9, 109G-14 and 109K-4 all come into service vs the P-51s summer-fall, 1944.
Bomber alts will be between 18k-25k I would think, depending, not always at 25k.
I see it as a rather balanced field actually. Both sets are competative, you can argue the fine points (and they have been argued over for decades) but the bottom line is that no one side will have super-duper a/c vs POS a/c on the other.
...so relax.
