Another new AirTag fan here. Bought 8 and put them in checked bags and carryons, as well as in family member’s purse (with her consent). Flew Greece-US via ATH yesterday.
3 of 4 checked bags never left ATH.; on arrival at destination,, immediately filed missing bag report and did not have to wait for the carousel to eventually empty.
Also, when family member disappeared to bathroom and did not return as our delayed flight was on final call, I was able to track her down in packed and chaotic duty free area in Athens (she refused to let me accompany her to bathroom, then got distracted on the way back).