I think, that minimal altitude for using parachutes should be radically increased. I also think, that after jumping out, it should take some time, before parachute open. Now, almost everybody is waiting and jumping out closely to the ground.
Parachutes should be easier to shot down. Now it is necessary to hit the pilot directly. I think, that parachute itself should be the hit zone also.
In my opinion, the distance around enemy airport, where it is not possible to get the tank after parachuting should be significantly enlarged.
Now, if you shot down two or three enemies near your airport, the time to destroy tanks before they reach the airport, is very short.