An airplane or helicopter with a tail hook should swoop over the vehicle and take it off the ground, like a hawk!! Just kidding-- it must be towed if it's interfering with aircraft or airport operations.
In the parking hardstands.
Vehicle will be clear of the wingtips and must be visible to personnel in the cockpit
Anytime the vehicle is on the Airfield
Both A & B
Vehicles without integral braking systems are required to be chocked when parked on an airfield.
Terminal or simply parking or tarmac
vehicles without an integral braking system.
Vehicle will be clear of the wingtips and must be visible to personnel in the cockpit
Vehicle lights on, permission from act ground, pilot informed Marshall in attendance
On the Parking Apron.
The same as it is for any other vehicle. What that distance is varies by jurisdiction. It may be anywhere from six to 24 inches.
If you have permission AND it is a PRIVATE airfield. I believe that all airfields under the jurisdiction of the Federal Aviation Administration (FAA) require a special license to operate a vehicle on an active airfield.