This achievement can be earned from the moment that you get control of Spyro and can be done alongside the achievement
Hop, Skip and Jump.
After opening the secret entrance to Sunny Flight by jumping on the platforms, you'll need to do a Loop de Loop around the first bridge that you see. Now you'll most likely hit your head when doing this but don't worry, you don't actually have to fly back under the bridge. You can do a Loop de Loop by pressing
RB on the controller. The following is a video guide for both
Hop, Skip and Jump and
Barnstormer.