The following is from Danella Photographic’s web site:

If Danella Photographic had a science editor, it certainly would be our good friend, Dave Tewksbury. Tewks has been a commercial photographer for over 30 years, and he was into digital photography before most of us knew what it was. Dave has forwarded the following information regarding new restrictions on air travel with lithium batteries:

There is a big discussion right now among press/sports photographers regarding lithium batteries. These new regulations may impact some of Danella Photographic’s clients as well. The rules apply to commercial flights, not just jets, as implied in the first sentence of the attached article.

The basics are that lithium ion batteries cannot be in checked luggage unless they are in the device using them (not likely you are going to check your new D3). The DOT documents are quite difficult to sort out with “aggregate equivalent lithium content.” The attached listing of common camera batteries and their equivalent lithium content may be helpful to have in your camera bag when traveling and dealing with TSA screeners.

The remainder of the article can be found here