Weird orb snapped during an air show, in Texas

On September 12, 2015, a witness was watching an Air show in Fort Worth, Texas. He caught several photos and, later, he noticed a mysterious appeared on one of them!

Witness report:

I was taking pictures of the Blue Angels flight team at the Alliance Air Show in Fort Worth, Tx. There was nothing visible in the sky during their flight. After taking a few pictures, I was looking at them and found one picture where a bright orb appears to be following them. It is not the moon and no other airplanes were in the area at the time.