Do AirTags work for checked luggage on flights?

Yes. AirTags use a non-rechargeable CR2032 coin cell that is below the lithium thresholds airlines restrict, and reviewers across travel-focused communities consistently report using them in checked bags. The bigger caveat is that AirTags rely on nearby iPhones to relay a location, so updates in cargo holds or remote airports can be sparse until the bag is near people again.