There are now different rules if you intend to fly this year with spare batteries. Here are the basics from the our ever-wary government and the FAA:   

• Spare batteries are the batteries you carry separately from the devices they power. When batteries are installed in a device, they are not considered spare.
• You may not pack a spare lithium battery in your checked baggage.
• You may bring spare lithium batteries with you in carry on luggage - see our spare battery tips and how-to sections to find out how to pack spare batteries safely!
• Even though we recommend you carrying your devices with you in carry on baggage as well, if you must bring in one in checked baggage, you may check it with the batteries installed.

While all this seems a bit too obvious to us, we figure that the elementary way of explaining the rules isn’t just for the casual business traveler. Check the site for more details.