Is it possible to make an aircraft unit that has a toggleable state which tells it to travel underwater if it over water? Think flying subs in X-COM 2.

yer gonna get a "lua it" response. brace for impact.

I know lua it is the solution, but I would like some pointers for approach.

what do the flying subs do in xcom? part of me wants to imagine wings unfold and bellyflop into water.

Basically, a flying sub is a sub that can go so fast underwater that it can go straight into airborne (makes sense, right?).
But the effect in this case would be to allow bombers to pop up out of the water near a coastline, and scouts to pop up from underwater too.

replaceunit->start wing open animation on create() of unit script->movecontrol to height->unleash hell?

All I can think of is unit replacement because we don't have much control over movement. That's quite messy though.