I think of this alot and i was wondering, what if we picked a country (rotating from one to the next to the next) and each time we came to a country we take the most produced aircraft to see service 1st and just go down the list.... Like U.S.was picked last so there out, and Germany is next (or whoever) and then so on until we run out of country's that produced and used aircraft in the war. then back to the US for the next round.
Then we would always know whats next (just not the when of getting it)
We would also see aircraft that may not have a chance of being "voted" in get in (like the Pe-2 and Tu-2)
Another option (witch i like better) but seems unrealistic that it would happen because of the flack it would make by people who want the uber-latest 51/spit/La/Zero, would be to start with country's in 1939 and make the aircraft that were used at the of the start of the war 1st.
then going to the next latest aircraft to enter service in the war. This being a seemingly straight forward plan, with the only trouble being that we will have a bunch of Biplanes running around until we get to more modern times in our development.