Although a RPS is a solution to the planeset problems, IMO I don't think this is the best way to deal with the problem. I would rather see some sort limitations on how many uber/rare/special varient aircraft a person could fly in a given time period. For example: You are given unlimited numbers of the main fighters for a particular country. (P51, P47, 109s, 190s, F4u-1D, C205, A6m, N1k, la5, yak9, typhoon, spit, etc.) You are also allowed to fly a certain number of special aircraft every 6 hours. For example, you get 5 sorties total every 6 hours in special aircraft like the: (F4u-1c, Do335, Me262, 190-D9, 109K4, Ta152, Tiger tank, and any other limited and/or uber planes added.) Given the correct settings I think that we can add these planes without filling the MA with them. Ideally you wouldn't want any more than about 5% of aircraft flying at the time to be one of the special types. If we find that too many of these planes are flying, we can impose other limitations on them, like 2 airfields per country (ideally in the far rear near the HQ) where you can fly these aircraft from. My idea here is that a country that has been pushed into a corner will be able to use a few of these special planes to better defend itself.
Picture the following scenario: The rooks have been pushed into a corner by the knights and bish. Just as enemy bombers begin to rain destruction on the hq and city, a small force of Me262s break through the clouds, shooting down many of the bombers. After an hour of bombing however, all rooks have used up their supply of special planes and will have to fly regular planes again.
On the ground a group of Panzers, escorted by flakpanzers make their way toward the rook city. Opposing them is a group of rook panzers, and also a small number of Tiger tanks. (Tigers could be considered part of the special set, and available at only rear vehicle bases.) With the help of the Tigers, the rooks are able to hold off the knights first thrust. Soon though, the Tigers are gone and the rooks begin to lose ground to the knight ground offensive.

I'm sure HTC can come up with a system far superior to a RPS similar to what I'm describing.
How does the above system sound?
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bloom25
THUNDERBIRDS