I think having a second vehicule such as a helicopter or plane that can fly like the jetpack, but with the speed of a normal vehicule would be a neat addition
But since it would be so good for travelling, it could have very low health and do lots of damage to the driver inside it when it blows up. But, it could only be hit at the same height as a jetpack user can be hit. A base couldn't be taken over while you are in the vehicule, and you can't get out of it while in flight. I think it would be fun