It's in XTAIDS, and I like the idea, Lere said something about mines being only for vehicles, but there's a sub minelayer...

So yeah, how about adding a hover minelayer?

And if so, maybe strip the minelaying sub of its land mines, as despite this being one of my favourite tricks, it would make more sense.

Vehicle minelayer = Land mines
Sub minelayer = Sea mines
Hover minelayer = both

All mine layers should be able to build all mine types, the ability to only build certain mines in certain places should be enough, after all a nonamphib mine layer cant lay a sea mine in the middle of an ocean