Rented movie disappeared from iTunes So, I rented guardians of the galaxy to watch on a plane ride, I downloaded it the night before I left so it would have enough time to download, I checked right before I left and it was fully downloaded, then when I went on the plane and no longer had internet connection the movie was no longer in my movies or in my unwatched movies.I never started playing the movie so I should have had 30 days. what should I do?
My first suggestion would be to launch iTunes and from the menu bar select Store -> Check Available Downloads

If that does not work, just contact Apple Support. Reference your order number, and they should push the download back down to you. 

They do have a 24 hour turn around on this, so do it earlier rather than later so you'll have it for your next flight!

http://www.apple.com/support/contact/