Nothing on their Web site.
Robert was able to find a USPS drop box; apparently it’s playing a game of hide-and-seek:
Outside the main entrance between the ticketing and baggage claim behind the Palm Springs International airport sign curbside. Regular blue mailbox.
Robert provided a couple of photos but they were rather small. I was able to find the sign on Google Maps. It may be easier to find if you walk to the main entrance and then turn around.
There is a Palm Springs Air Museum but it’s on the other side of the runway on Highway 111, if you have some time before your flight.
Last updated 19 August 2018