The Addon Manager has an option to remove moving vehicles from FSDT airports, and it IS "permanent", provided you also press the "Save to FSX" button, otherwise is valid for the current session only.
If you think it's not working, maybe because what you are seeing are the FSX default ground vehicles, and those are instead controlled by the default GSX Airport ground traffic slider.
In any case, I doubt that those few ground vehicles are causing stutters.
As discussed many times already on the forum, there's an Addon Manager settings, the "Anti pop-up" slider, that allows you to choose between saving memory and fps, or getting less pauses. If you set it higher than default ( which is 1 ), objects will be loaded earlier, so you'll get only one pause when the whole scenery loads, and probably a smoother flight afterwards, and the cost of increased memory usage and possibly fps loss. Your choice.
