AIRSHIP FOR RPG XP?

So I just uploaded the Mode 7 plugin into my game on the RPG Maker Xp engine. It's quite good, and now I want have an airship in it, similar to that of FF6's ability to control it's flight in a mode 7 environment. The problem is, I can't figure out how to do it. I watched this tutorial https://www.youtube.com/watch?v=a0EDDMQuNm8 and emulated each part. But I still can't fly over water or hills for some reason. Can anyone explain why? Thank you :)