I just looked over your initial question again numonic.
There's 2 different ways you could approach the movement stuff.
One would be to create 2 different "move" states. One for while on ground and one for while flying in jet mode.
Then simply switch between which one you want depending on his transformation state. This way allows you to tweak the settings differently depending on what mode you are in. eg: sensitivity / speed etc.
The other way would be to have a state before you get to your "move" state, that checks which mode the player is in, tweaks the settings then applies those to your movement.
eg: if flying then speed should be 10
as for the height stuff, try out what i did in my previous post above this one.
Grab the "set motor gravity" action from this thread
http://hutonggames.com/playmakerforum/index.php?topic=1392.0add that to the state that he starts in his "jet mode" and set gravity to 0, then use a "set position" action right afterwards, and set the value to whichever height you want the jet to fly at.
when you want gravity to take over again, use the set motor gravity again and make its value 20 or whatever is your default.