Flying Saucer UFO Passes Tourists Over Grand Canyon AZ, USA

This video is interesting as it is at a tourist hotspot and no tourist seems aware of any UFO hoax going on near by which makes this more authentic that usual. A fast shiny metallic disc passes at speed in the background of may people and just by chance, a lottery type chance, a tourist catches it on camera. There is no other explination for this other than a flying saucer! But is it an alien flying saucer? or a human built military saucer!