I retired from Boeing and worked at the Everett plant for the majority of my career. We always moved the AC from the factory apron across the bridge to the paint hangars with a tug. The AC are not fueled until ready for engine and other ground pre-flight tests. The engines are never fired up unless there are intake cages and blast fences in place. There are also FOD sweeps made to insure no foreign material gets pulled into the engine intakes. Furthermore, the “jet blast” would be destructive to property and the personal vehicles parked on the factory apron. In addition, it would require a certified individual to “drive” the AC under power.

I retired from Boeing and worked at the Everett plant for the majority of my career. We always moved the aircraft from the factory apron across the bridge to the paint hangars with a tug. 

The aircraft are not fueled until ready for engine and other ground pre-flight tests. The engines are never fired up unless there are intake cages and blast fences in place. There are also FOD sweeps made to insure no foreign material gets pulled into the engine intakes. Furthermore, the “jet blast” would be destructive to property and the personal vehicles parked on the factory apron. In addition, it would require a certified individual to “drive” the aircraft under power.