I've just received this UFO sighting report. The below photo shows a disk-shaped UFO, several hundred feet over Vancouver. On the right, there is an Airplane, which provides excellent reference. The Airplane is much smaller, and leaves an airstream in its track. The UFO seems to be moving fluidly and not disrupting the air around it at all. It may very well be just hovering in place, which would explain the minimal interference it creates around it.