Scripts are one thing but you need a lot more than that alone.
I think that TGC will try and implement both vehicles and flying entities into Reloaded but obviously we have to see how it performs and develops over time so that we could sensibly use them.
Vehicles : Now that we have bullet physics as the physics system I see no reason why you would not lets say be able to place a vehicle in your level and place them on a path and so they would move around your world and correctly follow the contours of your terrain correctly. A step forward.
Presumably you would therefore say be able to make a vehicle an enemy via a script that would shoot at you. e.g a tank. That may require other things as well so no idea if possible but not too unrealistic to expect perhaps.
Now derivable vehicles are another matter though I am sure if not supported a workaround may be found by someone. Eventually Reloaded my be updated to support that by default.
Flying Entities : Same goes here, not much different except these things clearly need to be able to hold a different vertical position in many instances a they Float in air as it were and require a different gravity setting amongst other things by are much the same as vehicles other than that.
I notice that Reloaded has an entity - that is a flying one - so what does that suggest to you?
These things should have the required Physics support available via Bullet Physics if TGC has not restricted but provided for it.
Now we have a third dimension and element that you could consider - and what is that you ask?
Water : of course - so water vehicles perhaps? Clearly you may be able to set up your speed boat and float it on water to move around - automatically say on a path if Reloaded provides for that.
Again some things above apply similarly here if implemented.
Now how about a modern Battleship game or a Pirate Game with Pirate Ships - possible perhaps? Someone has to provide or make those ships - which is complicated if you want them to look and behave well. May need advanced physics and collision. No good getting stuck in rigging, sails or falling through the entity eh! Can you climb to the crows nest to look out over the horizon? and much more.
What will you sail on - a flat calm sea : water plane and no waves always in the dolldrums?
The mind boggles.
Now a water world is a little problematical. Yes.
Underwater?
How about an underwater game? Atlantis? Submarines, Underwater warfare?
How would you do that - well not very well at least as things stand.
The water plane is just that a thin plane - its not a water block. Its set at a level. Can you raise it up? You have 20 levels high so if you have land above and sea below half way is 10 levels - not a very deep ocean and lower world above?
For advanced water and decent water games as well as any normal game you may need many other things too so any game made with Reloaded would be convincing and not just a very unprofessional attempt best avoided altogether - Weather, wind, water currents, water spray, bubbles and on and of course the physics and other things in place to accommodate them.
Some of those things need a very powerful and sophisticated engine and absolutely everything else that one would need to support achieving such things.
I can't imagine the difficulty and complexity leave alone the skills and hard work in so many game making disciplines that would be needed to make a Pirate game say. All those detailed models, sword fights, swinging from ropes, cannons shooting and recoiling, the music, textures, characters wigs, The ships sails blowing in the breeze? The onboard battles while the Ship moves through the water at 20 knots while the rain falls down and the sea sprays over the deck and you have difficulty standing while the ship bobs from side to side tossed about by the waves.
Forget it eh!
At least you have a water plane and the scene can go from day to night so you have a start
"You don't see 'im, till 'im come callin"