Vehicle based combat and transportation is expected to be a big part of PlanetSide 2
3rd person view has been removed from the game for infantry, although a third person view has been added for vehicles. Animations to enter and exit vehicles have been removed. 
Flight mechanics are being made more realistic, PhysX is powering the movement for all vehicles 
Vehicles will leave wreckage behind on the battlefield, the length of time they will remain for is still being balanced 
Around 30% of the vehicles available will be faction-specific.
Confirmed vehicle list
The following vehicles have been confirmed:
Other vehicles may be added later on, but these are all those confirmed for beta and early release.
Vehicle customization is possible using the skill tree. Players will be able to boost the horsepower of vehicles, for example, by training the right certs. Resources gained from strategic territory may also play a part - it may cost resources to add a secondary weapon to a high level vehicle. Possible vehicle weapons include chainguns, flak cannons and mortars.
The upgrades have a natural limitation in that there are tradeoffs. Adding better transmission might make your tank better at negotiating hills and tricky terrain, but at the cost of top speed. You may have to trade off top tier armour for better weapons.
Classes and Certifications
There could be aquatic vehicles and seaborne combat in the game. This would be new to the series.