Hi Johnnie,
I am sorry I did not know it is an FS2004 problem only

Solution: download
bae146 FS2004 cargo fixInstallation: replace the model folder, and the aircraft.cfg that came inside this file. It contains a new model with different cargo tractor/lifter than in FS2002.
Proper useage:
When FS starts, your engines are running (tractor cannot seen) If you cutoff engines (Shift+Ctrl+F1) nothing strange should happen... When engines are not spinning, and you open cargo door (Shift+E+2 quickly) the tractor will appear now.
Takeoff procedure: close each doors ony by one (Shift+E+2) for cargo door, and (Shift+E) for main door. If you start your startup sequence automatically (Ctrl+E) or manually, the truck and conatiners will suddenly disappear.
This way, you can fly without those cars

Sorry for inconvenience. Page and downloads will be soon updated.