I was an airline mechanic up until I retired 2 years ago. There isn't any carrier Under US FAA or EASA regulations that restricts the use of any airtag or similar device. Lufthansa was rumored to have tried, using the interference claim but quickly denied it when it's customers heard about it. Our shop actually put tags on specialized tools so the Tool Room could track them and since new generation tags can have a range of 90' to as much as 450' it help prevent tools from leaving the hanger or being left on the aircraft. The Avionics guys I worked with all seem to agree that for my purposes there shouldn't be any issues and just say to monitor the batteries in the key and tag. They will get you close enough to what ever they're attached to that if you can't se what your looking for you can tap your smartphone and the'll put out a tone like a ring. The ones made by TILE can be used in reverse if you have your FOB but can't find your phone, tap on them and the signal will have your phone ring.
I ordered one Apple Airtag and One Tile Pro. I carry a battery for my FOB in my wallet so should they drain the battery I can just toss a new battery in and remove the tag if I decide it's an issue. It'll take awhile to decide but I'm gonna give em a try. !