Not mine but anothers! {VXA}

http://www.rpgmakervxace.net/topic/4105-transferevent-processing-while-in-vehicle/page__pid__36569#entry36569

OK this person came out with a very good point

Rmvx ace dis-allows the use of scripts while in a vehicle, My guess is an instance script would help achieve this goal, though i have no complete idea how to make one, so i ask this very kind but critically Emphasized community to help with this little quarrel.

The inherent problem is that the default update_nonmoving method of Game_Player processes vehicle enter/exit code when enter is pressed, so it overrides event interaction.

If you simply overload that with code that processes a map transfer, you would no longer be able to get on and off vehicles.

What I would probably do is either hard code a one-off coordinate check into the vehicle exit script to see if the airship is above the crater on the appropriate map (which is a bit of a clunky and convoluted solution) or have a parallel process event checking the player coordinates on that map, and transfer the player to the crater map as soon as their X and Y is equal to the crater while they're riding the airship.

I'm sure one of the more experienced scripters will have an elegant solution.