The battery in an AirTag is a standard CR2032 button cell, such as you'll find in thermometers, car keys, or similar small devices. Lithium batteries in checke

The battery in an AirTag is a standard CR2032 button cell, such as you'll find in thermometers, car keys, or similar small devices. Lithium batteries in checked luggage are limited to 0.3g. A CR2032 has 0.1g. It cannot start a fire while in the AirTag any more than your car keys can.