Batteries on board
As of Jan. 1, 2008, the U.S. Department of Transportation has new rules regarding loose lithium-ion batteries in travelers’ airline baggage. (This rule does not affect alkaline batteries.) The ruling is to prevent any possible fires from accidental overheating or short-circuiting.
In carry-on luggage, any batteries actually installed in electronic devices (cameras, laptops, etc.) are allowed, but only two more rechargeable lithium-ion batteries are allowed as spares and they must be packaged in a plastic bag or the original retail packaging.

