Measures must be taken to prevent unintentional activation of the heating element while on board the aircraft. Examples of effective measures to prevent unintentional activation include, but are not limited to: removing the battery from the lighter; placing the lighter into a protective case; and/or using a protective cover, safety latch, or locking device on the lighter's activation button.
Each lithium ion battery must not exceed a Watt-hour (Wh) rating of 100 Wh; or for lithium metal batteries, a lithium content of 2 grams.
Recharging of the devices and/or the batteries on board the aircraft is not permitted.
See FAA regulations for more information.