I like Mandobles idea alot, very realistic, hope HiTech reads it. Would alleviate the lemming swarming of perk planes from 6k out...
making people use perk planes more, making people burn perks, making people want more perks, making people even the countries out over time in seek of better perk modifiers and flying a wider variety of aircraft (early/mid war) for better enemy rating.
We seem to be stuck in a rut where perk planes are avoided because of the gang-bang factor which is not how it should be. Pilots in WW2 loved to be the first to get a new model or plane type to try. As it is now we are inundated with the "free perk planes' like La7, P51D, Spits and Niki's and not much else.
The perk system is an economy of supply and demand and there's not much demand, so the incentive system of the perk modifiers is not terribly effective.