I have noticed that a lot of people want the clickable interior from Take On Helicopters in both aircraft and vehicles. Understandably, you guys at BIS aren't going to implement this feature due to it not being something relevant to Arma's needs + Time / Engine / Resources limitations. But I'm sure we can all agree that a more immersive experience with the ability to interact with the crew cabins / etc. would be super awesome and make things fun. This is why I'm suggesting a simpler approach to this problem: animations for actions inside vehicles. What this basically means is that when you preform an action in a vehicle, for example turning on the engine or switching off headlights, there would be an animation to go along with it (Excluding Get In / Get Out actions, they already have them). I think that this would both look really cool and give everyone something neat that they like, both for the people who don't want a clickable interior and those who do.

A way that might possibly make this easier to do is to have several base animations, then adjust them to the different vehicles:
• Aircraft Startup Sequence (1. Battery 2. APU on 3. Throttle 4. Ignition 5. APU off.Something like that)
• Aircraft Shutdown Sequence
• Car Engine Key Turn (Same thing for start / stop, there isn't really any difference)
• Headlight Knob Turn (For the headlights, usually on the right side of the wheel)
• Generic Button Push (For anything involving buttons, like "Manual Fire")
• Generic Lever Flip (For anything... Levers. Like "Gear Down")