How can i recover my purchased itunes movies on ipad?

If you are in a country where films can be re-downloaded and they aren't from studios that don't allow it and the films are still in the store then they should appear in the Purchased tab in the iTunes store app. If they don't then have you got copies of them on your computer and/or on a backup that you could resync to the iPad ? If not then you can try contacting iTunes support and see if they will grant you a re-download (assuming that they are still in the store) : http://www.apple.com/support/itunes/contact/ - click on Contact iTunes Store Support on the right-hand side of the page