Now this may sound crazy and might not be the problem. But have you checked the order in which your scenery is displayed? This is in the Scenery cfg file.
The one thing I have noticed about FSX and FS9 is when you add any new scenery FS will put that scenery as the first entry therefore creating that scenery first.
Now this can be a problem in certain situations. Which is why you might go to a airport and find a plane or a ground vehicle in the middle of a hanger
This is because of the order of scenery. My biggest reason to keep collision turned off, as you can go to a airport and find your self in the middle of a hanger and than the sim crashes because of this. What I do is after I Have added any new scenery I will put it at the end of the list causing this scenery to be displayed last.
But like I said this might not be your problem but the fact that you state you see the baggage cart off the ground in some places makes me think it might be because of the scenery order.
Since I have never looked as to how the ground vehicles are created this could also be cause by a contact problem. But I doubt it since you do not see it off the ground every where you go.
One has to remember to think like a artiest painting a picture you have to paint things in a certain order to create the effect you want.
FS works the same way it goes down the scenery cfg file painting pictures so if you get 1 out of order strange things will happen.
I usually create the default scenery first than make changes to that. So make sure that your REX scenery is being created last not first.
Trust me it can make a difference.
