[David603]

Oleg Maddox seems to be attempting this with Storm of War, in that planes with be factory fresh when new and degrade with use in missions. The effect will be simulated both visually and with a loss of performance and reliability.

Interesting for offline play

But I doubt it will factor into online play

For online play, I believe the solution discussed was to set each plane at a level of wear that could be considered typical for the type. For example, planes on both sides during the BoB might have quite low levels of wear, but a late model Bf109 would have lower levels of reliability to begin with and would suffer from a higher level of wear, as would be historical.