I just tried to find the thread where Reddog explains individual aircraft accounting isn't possible on BoX, but failed.
It appears that it can now be done, here are Coconut's server rules:
layers are free to spawn in any available plane at the rear airfield and at an airfield in a region with an ongoing tank battle. At other airfields, they can only spawn in a plane that they have previously landed there. The campaign keeps track of how the number and type of planes for each player at each airfield. The number of a specific plane model at an airfield is decreased whenever a player spawns in that plane at that airfield. Additionally, players have a “cash reserve”, earned by destroying targets (not implemented yet) or running supply missions (not implemented yet). This cash reserve can be used to “buy” the right to fly a plane at any airfield. This mechanism is intended to avoid plane wasting by new impatient players that take off close to the action, get killed 10 minutes later, and repeat the operation, resulting in quick depletion of planes at the frontline, often for too little result.
There seems to have been a few steps made on the BoX front recently, either by discovering hidden features, as a result of the v3.002 upgrade or simply through the community finding work-arounds. In addition to the aircraft accounting, I've found some notes of an alternative mechanism to implement recon... although not perfect, it offers some functionality at least.
It's been nearly six months since we last did an assessment. Sounds like it might be time to dig out the compliance list and go through it again to see what is feasible now.