Airborne?

I've been trying to obtain an airborne effect for models that do not have a hovering animation, like for example make an object deccelerate and accelerate up and down. I've managed to make it in GUI (and don't ask me to make it in JASS, I don't know JASS), but I've been having an annoying problem: I've used 4 unit groups to do this, one that accelerates up, then deccelerates up, then accelerate down and deccelerate down, and back to accelerating up. In theory, it works just fine, and from what I've checked, it has to work correctly. But whenever the flying height has to change direction from moving downwards to upwards and vice-versa, the model instantly moves upwards or downwards and carries on with the triggers. It shouldn't do that. Copying the triggers is too tiresome, so I've attached the map so you can see it for yourself. If you manage to fix it, just explain what was wrong and add your name to the authors in the map description and if you want add it to the "Press ESC" message too.