This doesnt necessarily have to be an independent mod, it could use vce as a base.
New vce event could complete this task, a vce variable replacer that enables/disablesa person's ability to spawn vehicles.
This is how i plan to do loading variables for my city rpg.
[Onplayertouch] [client] [modvar] [vehicspawning] [set]
then when the person goes to spawn a vehicle, the game doesnt allow them to because it is set to 0 meaning no. do a 1 for when they go to get it.
doing individual licenses, for planes, cars, etc, would be slighty impossible seeing how no specific distiction is made between vehicles, only values such as sinking rate, gravity, etc.
The way my city rpg is set up allows for this to occur without the need for a mod like this, because i own every building surface available. Just some simple vce and setbrickasplayerownership events and im good. The only mod that would be required for this is restricted building bricks-disallowing anyone to build a spawn brick.