Freedoms / Rules
Personally, I feel like the air rules are too strict. I feel like having the freedom to use it as an escape or use it illegally in some way could work. Planes and Helicopters are really expensive in the run long so you wouldn't see it abused too often. I also feel like instead of revoking the license and yoinking the helicopter or plane they could impound the vehicle with a heavy fee or temporarily revoke your license and give it back once it is over.
There could also be an air traffic radar or something that the Police could access that reads all air traffic. They could also make it more skill based and make it so that it only detects at a certain height. I feel like having more freedom with planes and helicopters with only heavy fines/impound fees could open a ton of RP opportunities.
This is just a suggestion but it would be cool to see cargo or even illegal jobs for planes/helicopters that aren't 12 million dollars. It could really open the lock on air based RP which I personally love and other enjoy. I know scripting and developing is long and hard work but it would be cool to see it in the future.