The Transport Security Administration (TSA) has mandated since 2008 that no loose lithium ion batteries may be packed in with checked luggage. This means that all your spare batteries will be going in with your carry-on, which may not be a bad thing if your flight doesn't have any in-seat power.
If you don't want to deal with the added shoulder weight, you'll have to pair the lithium ion battery with the device. (Read more about the rules here.)
New findings brought to light by the Federal Aviation Administration (FAA) say that lithium ion batteries are sensitive to heat and can ignite in a hot environment. Of course, that is a characteristic of batteries in general, but the new research could lead to an even further more restrictive set of guidelines for what people can bring when flying.
The FAA also acknowledged publicly that the UPS 747-400 plane that crashed in Dubai earlier this year was carrying a large quantity of lithium batteries.
