[jamesqf]

Still, there's no indication that the car was drafting. In fact, it probably couldn't have been. The car would have to have been VERY close for the hatchet to fall directly to the windshield, since there's almost no height difference between the truck bed and the hole in the windshield.

Seems more likely that it fell, bounced up, and spun into the car that was a good way behind. And it almost certainly had to have been spinning: if it just fell off and went directly to the windshield, it would have been moving at almost the same speed as the car, so it wouldn't have penetrated.