HT4743: Apple TV (2nd and 3rd generation): Purchasing and viewing TV showsLearn about Apple TV (2nd and 3rd generation): Purchasing and viewing TV shows
Currently Being ModeratedAug 17, 2013 3:52 AM (in response to dominicob)
Open the iTunes app on the iPad and download using the Purchased link on the bottom right.
Alternatively in iTunes on a computer, go to the store home page with the house icon and use the Purchased quick link on the right:
...select and download stuff then sync to ipad or playback on the LAN using Home Sharing.
AppleTV doesn't store anything.