Could it have been a motorised glider?
Posters comments:
Yah so me and my friend were coming back from the local arena in Payson AZ on our horses and the horses got spooky and we looked up and Saw a light in the sky and had the camera with us, the last part is all blurry because when it started "Morphing" it messed with our camera, after it was done is dissapered and the camera started working...