Black UFO appeared during Hickory Air Show in 2012

On October 2012, a witness took photo to the Hickory Air Show, in North Carolina (USA). On several pictures, he has noticed a black oval-shaped UFO flying near aircrafts. What is it?

Witness statement:

Photo # PA 19 5773 taken at the Hickory Air Show on October 19, 2012. In prior photos the oval disc like subject can be seen moving from left to right toward airplane #40 and #44 at a high rate of speed. It appears to be oval, dark center, white outer body and has what appears to be a magnetic like power field. The only sound at the time was hundreds of people enjoying the air show and the airplanes in flight. This unknown flying object has been observed in various other photos over the last two or three years. At various times more than one have been photographed together. They do not appear to be mechanical and move in unison as to be controlled by a central control.