When a carry-on bag is checked at the gate or at planeside, all spare lithium batteries and power banks must be removed from the bag and kept with the passenger in the aircraft cabin. The battery terminals must be protected from short circuit.

Yes, you can fly with power tool batteries, but they are subject to strict FAA and TSA "Fire Safety" regulations regarding lithium-ion technology. In 2026, the rule is that spare (uninstalled) lithium batteries must be in your carry-on luggage; they are strictly prohibited in checked bags because of the risk of "thermal runaway" fires in the cargo hold. If the battery is installed in the tool, the tool can be checked, but it is still safer to keep the battery with you in the cabin. There are also "Watt-hour" (Wh) limits: batteries under 100Wh (most standard drill batteries) are allowed without restriction in carry-ons. For larger batteries between 100Wh and 160Wh (like high-capacity 6.0Ah or 9.0Ah packs), you are limited to two per person and often need airline approval. Any battery over 160Wh is completely prohibited from passenger planes. To prevent short circuits, you should place each battery in its own plastic bag or cover the metal terminals with electrical tape to ensure a smooth trip through security.