I know that you can do it with Google Play movies. You have to use the Google Play Movies app, which is free from the Chrome Play store. Once you have that installed, any movies or shows that you own will show up when you open the app. In the bottom right hand corner of the movie “card” there is an icon to download that movie. Click on that, it will save the movie to your Chromebook, and you can enjoy your flight with your own movie selection. I find Chromebooks especially good for this use because of the excellent battery life compared to many laptops (especially if you turn down screen brightness a bit), plus you get a larger screen than with most tablets.