There's a limit on what amount of lithium you can carry on an airline. I'm not sure right off what that limit is. Something like 25g across 2 batteries? I do know that you absolutely can NOT have spare lithium batteries in your checked luggage. Be that spare batt's for your camera, laptop, or phone. You can have 2 in your carry on, but again, there's a limit on the amount of lithium. I have no clue what 25g lithium content would equate to as far as mAh ratings or anything.

oh, here, I found this snippet at bit-tech...

"The rules are, as seems to be standard for airline regulations, somewhat oblique: you can carry batteries with up to eight grams of “equivalent lithium content” per battery so long as you don't exceed two spare batteries with an “aggregate equivalent lithium content” of 25 grams. If the battery is a straight lithium type (as used in some digital cameras) rather than lithium-ion or lithium-polymer, you're limited to two grams of lithium per battery"

Pretty vague. I think they might hassle you over the rc packs in your luggage, but maybe not.

J.