iPad 3 app won't transfer an app to new iPad Air 2 I plugged iPad 3 and iPad Air 2 into laptop through iTunes. All apps are showing except for "Geocaching". I cannot drag it from iPad 3 to iPad 2. All I get is a box with the line through.

How can I get this app I purchased on the iPad 3 on to my new iPad Air 2?
On the iPad or iPhone - go to Settings, scroll down to iTunes &amp; App Store, select and scroll down to Automatic Downloads to have every purchase (even free) downloaded to every device.