My late father-in-law was a P-51 driver in the 3rd Air Commando Group working the S'West Pacific theatre during "The Big One". He did some training in the under-performing, rear-engined, P-39 while stationed in Eagle Pass. I have some of his flight logs books along with a Japanese pilot's kneeboard.
He did relate, while out on "free" training flights in the wide open spaces, that automobiles would actually leave he road when he made low, head-on passes at them. At that "altitude", heading and speed, it was impossible for the car driver to catch any ID number on the aircraft but hqtrs was constantly admonishing the students to, "straighten up and fly right". Didn't happen.
Monte