What about fitting small ships in them? Like fighters
I refer you to previous posts regarding this idea. Namely, to keep the ships in you would need doors of some sort. I do not know if you can actually have doors that work on a vehicle. Either way, it would be difficult to make the model as so there are the proper ship receptacles. Also, I think this implies the capability for players to get out of the fighters and into the main ship and vice-versa. We have discussed nomount scripts and the like.
tl;dr: Sadly, I don't think so. It would be cool if it was possible though.