Look what he's up to now. It's amazing how common the "that hillside is full of warbirds/jeeps/whatever" story is, and how geographically widespread. I worked on a north-west Australian cattle station that included an abandoned WW2 airfield, and more than a couple of people had wasted time and money digging into bits of it looking for them.
Near my dad's home town in Hertfordshire, there was an old 8th Air Force base and relatives of mine knew about people who claimed there were whole P-38s, motorbikes, trucks, jeeps etc buried, although the status of the story was "you don't want to listen to old Stick, he'll believe anything". Oddly enough, if they waited long enough they were almost right, because the Americans continued to use part of the site, and allegedly some of it was used for something spooky during Iran-Contra. There are similar stories I'm aware of about a couple of places in Yorkshire.
I presume it goes back to genuine tales of how much surplus kit there was sloshing about, and how much of it was basically thrown away, and perhaps to a deeper awareness of the wastefulness of war. It's also very similar to the cargo cult - like the intersection of buried treasure and cargo cultism.