飛行機に乾電池・リチウム電池を持ち込める？（米国TSA・CATSA規則）

持込可：航空保安基準において機内持ち込み手荷物として問題なく持ち込めます。

受託手荷物：受託手荷物（預け入れ）として問題なく預けることができます。

Standard carry-on baggage size allowances apply; TSA publishes no individual numerical cap for personal use.

Yes, passengers may use Batteries (AA / Lithium) during flight in compliance with crew instructions.

Power banks and lithium batteries under 100 watt-hours do not require formal declaration at domestic security checkpoints. However, if your spare battery is between 100 and 160 watt-hours, you must declare it to your airline ticket counter prior to boarding for carrier safety approval, and declare any damaged or recalled units.

If a power bank or spare lithium battery is discovered in checked luggage, airport baggage screeners will remove and confiscate it without passenger notification to prevent cargo compartment fires. At security checkpoints, unlabelled banks or units exceeding 160 watt-hours will be denied boarding and surrendered to security.

Yes — alkaline and other common dry batteries (AA, AAA, C, D, 9V, button cells) are allowed in carry-on and checked bags. Cover the terminals of loose ones to prevent short circuits.

Spare (uninstalled) lithium batteries and power banks cannot — they are cabin-only under FAA rules, limited to 100 watt-hours (ion) or 2 grams of lithium (metal). Batteries installed in a device are fine in checked bags.