It is best to check with your airline. 

International flight regulations prohibit heated tobacco products like Ploom in your checked luggage (the suitcase that goes in the hold). 

Some airlines might let you take Ploom in your carry-on bag, but you won't be able to use Ploom on a plane or while you're on board.  You should also check the legality of Ploom devices in the country to which you are travelling.