Devices containing lithium metal or lithium ion batteries should be carried in carry-on baggage. Most other consumer devices containing batteries are allowed in carry-on and checked baggage. For more information to portable electronic devices, see the FAA regulations.

When traveling with an electric toothbrush, the most important rule is to keep it in your carry-on luggage rather than checked baggage. Most modern electric toothbrushes are powered by lithium-ion batteries, which aviation safety regulations (like those from the FAA and EASA) prefer to keep in the cabin where any potential thermal runaway or fire can be quickly addressed by crew members. To prevent the toothbrush from accidentally turning on and buzzing inside your bag—which can be embarrassing or even cause a security concern—many travelers remove the brush head and store it separately. If your toothbrush has a "travel lock" feature, be sure to engage it; otherwise, placing it in a hard-shell travel case is the best way to protect the power button from being pressed by other items. If you are on a long-haul international flight, keeping it in your carry-on also allows you to freshen up during a layover or before landing. Just ensure that any accompanying toothpaste is in a container of 3.4 ounces (100ml) or less to comply with liquid restrictions at the security checkpoint.