buy rechargeables the only way to go! get the highest mili amp battery you can find, they come in all ranges from 1000mAh to 2800mAh. the number will be written on the side of the battery. (it's not always on the packaging) They will last 3 to 4 times longer than disposable batteries. Buy the highest mAh battery you can find, the higher the that number, the longer they will last. Normally you can buy a set that comes with charger and then you buy another set of batteries only.( that way you can swap out on the go) they will last years.
And yes, carry batteries in your "carry on" luggage. Airlines are getting touchy about carrying batteries in "checked bags". I always carry all my camera equipment, batteries, and chargers in my carry on bag.