Why not discount perk costs of certain vehicles and aircraft to veteran Players? It potentially makes certain aircraft and vehicles "free" such as the Tiger 1 and 2, along with the Me234 and Me 262, but after 10 years I think that its plenty enough loyalty to reward those players.
Scale perk costs according to Years of Service: 1 year: .75, 5 years: .5, 10 years: .25 So a Me 262 at 100 perk points to fly would cost a "veteran" player 75 points at year 1, 50 points at year 5, and 25 points at year 10.
You could even award a higher perk award to veteran players than a relative newbie along the same scale 1 year: x1, 5years: x2 10+: x5. I was thinking this would initially unbalance the game, but when the game has a list of dedicated players then the trade off its worth it because fewer people will actually be able to use those craft routinely (and at a lower cost) than racking up point per kill norms. So it would keep the balance in the end I think.
Personally as Veteran of two tours in Iraq (and 20 years total time in Service[ US Army/ US Army National Guard)- getting to play with a great group of folks here on Aces is all the reward I need. I have played the game off and on since it was shown on the History Channel and Discovery in 2000, and I keep coming back because of its appeal as a game and for the community- which personally I feel is a lot better than say Ultima, World of Warcraft, Champions on Line, City of Heroes, and Guild Wars or Even Quake and Quake Wars... but thats just me.
In either case

to all the Vetrans here and in our Armed Forces Past, present, and future!