Fans try and guess what the things are in the videos before it is revealed on the show. This is the cases' Arizona Lights fan speculation page.
The Original Video[]
Some fans believe that this was a reflection on the lens of the camera of the river bed below. There is a river bed below the advantage point and fans believe that the lights in the sky were reflected off of the camera lens via the river.
Scientists have since proven that it is simply natural. Ball lightning is lightning that is in a ball-shaped form. Fans were upset, and some have even called this a lie.
The Night Time Investigation[]
Due to the silence of the craft seen in the skies in the Night Time Investigation there is no way it could of been an aircraft. Fans believe that this was a weather-balloon with a light underneath (for detection) being blown away in the winds of Arizona.