No matter what you are doing as a player - great ace or hack - it seems to be a time thing for you to get the aircraft upgrade.
In WOFF you receive the better planes by higher rank, not by victories.
(I find that perfectly okay, cause we are unreal aces, who have fallen hundreds of times,
but still grow the same combat experience).
In the "Pilot Enlistment" screen you can see, that there are low, medium and highest ranks,
and the aircraft each rank receives, are listed there.
When you switch through the months per arrow button, you can see, how the same aircraft,
which first came to the highest ranks, will go to the medium, and later to the lower ranks.
This "Enlistment" menue is a brilliant show, cause you can check out almost EVERYthing there.
For those who didn't know yet: you have a "Manual Enlistment" at the bottom right.
If you click that, you will get to an "all selectable" menu.
You can pick a nationality, a year, a month, even a day you want to start -
and you can check each and every squadron with this method, to find the perfect one for you.
Then select the rank you need for the desired airplane - what more do you need?
That we have to wait until we will receive the next better aircraft - that is only
how it felt to be a simple pilot. You had not much to say; you had to take what
you were given. It's the military, after all.