Go into your settings & turn off for Airport grn scenery by moving the bar all the way to the left.. Seeing Aerosoft uses there own vehicles this will eliminate all default FSX Vehicles.. if you still want traffic just move the bar to minimum airport ground traffic but the default Pushback will then still be at some gates but not as many..
I ended up having to remove FSX ground traffic by telling it that I didn't want any because I kept having trouble with the default grnd traffic running into my ERJ's & when they went to leave the aircraft, they run right into my wing.. Plus the moving vehicles wouldn't always stop for you when your trying to push back causing aircraft crash, so much as I hated to eliminate ground traffic from moving around the airport, I took them off to spare me the crashes.. Plus Aerosoft & soon to be GSX have better looking ground equiopment then Default vehicles look anyway..
For example, with the default tractor & cart both move together instead of seperate. GSX tug actually looks like the real thing & acts like the real thing so really I don't really miss having the default grnd traffic on at all now... I'm looking forward to GSX once its released.. I'll still keep AES around for the animated jetways & for the cleaners to come clean my plane..