Help With Flying Units

I need some help. I made a ship that flies at 0 height, so it can float on deep water, but how can I stop it from getting on land? I tried using small line of sight blockers, but those don't help. Can some help me? Basically, it has to be able to stop and no longer go. Thanks in advance.

tft or roc?

I'm using Reign Of Chaos 1.10. I'm getting The Frozen Throne in a week or so.

wait for TFT, walking/swimming on deep water are both movement type options. you can just make the guy have a boat's movement. :D

or buy tft now! as soon as possible!! i bought it right when in came out OMG ITS SO GOOD!