A:Answer Hi Otto, somehow I doubt you can play movies off this Chromebook when it is offline, because it (like most Chromebooks) has very limited Hard Drive space. That said, there is a slot for an SD card and those can hold a lot of movies if you buy a good card. I admit though I have never tried to play a movie on this chromebook from SD Card. But now I want to try :) If it works, that seems to me the likeliest way to watch movies while you are offline, for instance in an airplane or outer space.
