Last summer on a trip to Italy we took our tandem separated and packed into two boxes. We attached Airtags to each frame section. Leaving Dulles one of the boxes didn't appear to move from the main terminal while checking the Airtag status. The other box was on the plane as reported by the Airtag. I was miserable thinking that we would start our trip with only half a tandem arriving in Rome with us to begin our trip. Alas, upon arrival in Rome, both boxes appeared at baggage pickup. Both Airtags worked and reported their locations on the return trip home so there was some sort of glitch on the outbound journey. In the end, all was well, but Airtags are not perfect.