In the most recent SITREP (74) we have been notified that firing from vehicles will be staged on Dev Branch sometime later this week.
Firing from vehicles will be great, but one thing needs to be taken into consideration: backblast. Firing missile launchers from inside helicopters or cars should cause considerable damage to certain vehicles or their inhabitants. For example, firing a PCML or RPG-42 ("hot launch" systems, where the rocket ignites when the trigger is pulled instead of being pushed out and then igniting like the Titan) while the back is pointed at another passenger's head should kill or severely injure them. Similarly, a point-blank backblast into the cockpit or engine of a helicopter (especially in a closed canopy) should cause damage to instruments, injure (stun would be preferable but we don't have that yet) the pilots and passengers, and cause any other damage that should be associated with such an event.