It broke free from a private plane after it took off from Monterey Regional Airport on Thursday.
The 75-pound door fell a thousand feet. It crash landed on the roof of the El Castell Motel.
No one was in the room below at the time, so no one heard it hit. No one noticed the door until Friday. That's when it was removed from the roof.
FAA officials are investigating how it came off.
The pilot heard a noise, but didn't realize it was the door.
The pilot returned safely to the airport.