In Dragonfly Falls, when you enter the area near Hunter's cave, you'll be on a cliff, where you can glide to a certain plateau that you can usually only get to when wall-jumping.
Glide to it, and fall into the wooden wall-jump pole on the left. You should fall into some water floating in the skybox. Swim underneath and find your way to the regular level. You should now be flying around freely until you're hurt, go underwater, or talk to Hunter (you can go into his level, by the way).
Watch the video