My wife has a dog boarding business, and a good number of the dogs have air tags attached to their collars. Most of the owners geofence around our home/boarding facility so that we don’t get constantly nagged by them. But when we drive one of these dogs somewhere (usually to walk/exercise them on a hiking trail etc) we often get alerts on our iPhones about unrecognized air tags that have been nearby us for a prolonged time. If will include a map showing our track and where/when the air tag was detected each time along the way.

So while I don’t use them personally I’ve seen that they do indeed work quite well. Maybe next time I travel I’ll get one for my luggage.