iPad sync movies bought on Appletv
Did you purchase or rent?
-If you purchased make sure you are signed in with same Apple ID on iTunes
Open iTunes on your computer. (You can download the latest version of iTunes here.)
Make sure that you have "Show iTunes in the Cloud Purchases" enabled in your iTunes preferences by going to iTunes > Preferences under the Store tab. Then, click OK.
If you're not already signed in, choose Store > Sign In, and enter your Apple ID and password.
After you've signed in, click the Library button located in the upper-right of the iTunes Store.
Navigate to your iTunes library for the respective content type you wish to download using the content selector in the upper-left. Choose Music to download songs, Movies to download movies, and so on.
Locate the item or title you wish to download.
Click the download icon to download that item.
Note: The download icon for previously purchased movies is located to the right of the movie title. To download previously purchased apps and books, you'll need to navigate to the Purchased page under the Quick Links section in the iTunes Store. For more information, follow the steps outlined below for iTunes 10.7 or earlier.
Follow this article if more information is needed.
http://support.apple.com/kb/ht2519?viewlocale=fr_fr