That's 91 miles, nearly the distance from Knoxville to Chattanooga. I'm not an optics guy but that seems pretty far away. And do we even know that the cameraman was trying to keep it in the frame at that time? In the video I've seen he was not.
But this is all academic since we have a picture of the plane flying inland from the west:
That's an illusion created by the atmosphere and a poor quality webcam camera. ;^)