Earlier quoted context omitted.
What do you mean "active tracker"? As far as I know airtags have a battery and aren't passive devices.
AirTags doesn’t report its location, the iPhone or other iOS devices report nearby AirTags. That’s the difference between an active tracker that has its own cellular connection.
The rules are about there being a lithium battery in it (there is) and whether it has a radio transmitter (it does, airtags transmit Bluetooth signals).
Lithium batteries are not allowed in checked baggage. Transmitters are allowed only if turned off.