[sgerenser]

PODS are advertised as having a transparent roof for light, most likely polycarbonate. Not sure if that would be sufficient for an AirTag signal if the rest is metal, but I suspect it would be.

[AmVess]

Aluminum frame with fiberglass panels. I put a cellular GPS tracker in the one I rented and it worked fine.

[lesuorac]

My experience with PODS is it's basically a smaller shipping container with a rolling door.

I didn't test airtags at all but they definitely stack them pretty high up in a warehouse so idk if an iPhone is always going to walk by yours.