I have had the airtag on a checked bag ping me while in the aircraft before but while the bag was being loaded.. must have been the baggage handler's phone or something nearby that picked it up.. At the time I was in a window Polaris seat in the forward cabin and the bags were coming in to the forward baggage doors..

which makes me think, there must be SOME BTLE drain for phones which are around lots of airtags often, being the primary 'locating' device and communicating device to the cloud. I wonder if the baggage handlers and or check-in agents have seen or will see more battery drain due to all the tags people might ultimately be using for baggage tracking. Certainly an on the tarmac baggage operator is going to see the highest increase in these as they are probably more often around the MOST number of possible bags.