......... it wasn't the Vanagon that was moving - it was the
>plane, which clipped the top of the Vanagon (either on takeoff or
>landing, I forget which).....

...on takeoff...  and then flew with the top of the Vanagon stuck to the
left wing, cam around, landed, and taxied back to where the collision
occurred.  Probably not.

Broken glass at the plane:  plane stopped and backed up to the point of
collision??  Not likely

Plane parked on taxiway, probably at night, Vanagon driver going like a
bat out of hell in the dark, oops!!