Q: I bought a movie on my iPad air 2,

Hello there, carmen2171.

To download previous iTunes purchases again, the following Knowledge Base article offers some great steps to follow:

Download past purchases - Apple Support

Before you begin

1. Sign in with the Apple ID that you used for the original purchase. Use these steps to see which Apple ID you used to download an item.
2. See if the content is available for redownload. Previously purchased items might not be available if they're no longer on the iTunes Store. If you changed your Apple ID from one country to another, you can’t download items you purchased in a previous country.

If you're using Family Sharing, you can use these steps to download your family member's content.

Download previous purchases on your iPhone, iPad, or iPod touch

Make sure your iOS device meets these system requirements:

• iOS 4.3.3 or later
  You need iOS 5 or later to download items to iPhone (CDMA model).
• iBooks 3.0 or later to download books

Movies, TV shows, or music videos

1. Tap Settings > Videos and make sure Show All Videos is on.
2. Tap the Videos app.
3. Tap Movies, Music Videos, or TV Shows at the bottom of the page.
   
4. Find the item that you want to download.
5. Tap the Download icon.

If you continue to have issues with your purchase, you can report it following the information in this article:

Report an problem with an item you bought from the iTunes Store, App Store, Mac App Store, or iBooks Store - Apple Suppo…

Thanks for reaching out to Apple Support Communities.

Cheers,

Pedro.