Capt Squelch
I doubt very much that your theory is correct, the resultant spark from touching the nozzle to your open fuel pipe would have surely caused an explosion by now.
My guess is that car tyres contain a lot more carbon and conducting material to prevent static when you step out of the car, and it is believed to reduce car sickness as well (hence those black dangly things on the back of Trevors XR3).
An aircraft builds a charge by flying through (friction with) air, hence static wicks, and again, I don't think a car with four tyres permanently attached to the road doing less than 70mph will create such an amount of static.
Rod