Don't worry that you might not be allowed to slip an Apple AirTag into your luggage for your next flight. As The Points Guy notes, the Federal Aviation Administration (FAA) has stated that AirTags are allowed on checked baggage. Any item tracker whose battery has under 0.3g of lithium is clear to fly. You can track your suitcase without fear of the airline taking action.
The clarification comes after worries Lufthansa might ban active AirTags in baggage. There were concerns the German carrier would interpret the International Civil Aviation Organization's (ICAO) guidance to forbid any lithium-powered tracker that can't be turned off, including AirTags. There was speculation Lufthansa wanted to forbid the tags to mask problems with lost luggage and other air travel problems. However, ICAO can only issue guidelines — it's up to officials to adopt and enforce rules, and there are none pertaining to these devices in Germany or the US.
Lufthansa issued its own statement clarifying that Apple's devices are allowed on flights. Both the airline and German regulators have determined that item trackers with small batteries and low power "do not pose a safety risk." The company added that it sought exemptions for AirTags and similar tags for checked luggage restrictions.
The FAA and Lufthansa statements theoretically settle the matter. While we wouldn't completely rule out governments or airlines altering their stance, there haven't been any reports of fires or other incidents that would prompt a change of heart. You can safely use AirTags, Tile trackers and similar find-my-stuff products to provide some reassurance during your next vacation.