When travelling, it is smart to bring your iPad with you. Read a book while in the airplane or when you are in the train. The problem that occurs often, is that you’re deep into a book or in a movie when the battery of the iPad is drained. There usually no charging points in trains and airplanes.
A good solution for this problem are portable iPad chargers. I made a list of the best portable iPad chargers here. I will update the list when I discover more good chargers.