Something like this happened to me at Big Bear. Got to the hotel after a day of sightseeing only to find horror of horrors no key! Tricky since the spare set was 600mi away in Arizona and would involve a truly humiliating admission of what I'd done.
Ended up re-visiting every scenic overlook, searching the parking lots I'd visited, etc., walking all the trails again but nothing. Then a flash of inspiration - I'd visited the supermarket. Last desperate chance - I called them and Oh yes said the manager we have got some keys! Phew!
So the moral is: if you keep aircraft keys in your pocket, think of places where you might have reached in for money. And link them to your car keys so you can't leave without them!