When driving a vehicle, you do not only steer with the WASD keys, mouse movement controls the vehicle, too. I am (personally) very annoyed of this behaviour and would suggest to replace steering with the mouse with looking with the mouse, i.e. you steer with WASD and look around with your mouse. This would be way more natural to me and probably also to other (new) players. (Because it is similiar to the infantry behaviour)
- Legacy ID
The workaround is to enter freelook mode (2x left alt), but you have to remember to exit it if you switch to a gunner's position. It'd be nice if mouse defaulted to freelook while driving, but aiming when entering gun positions.