>When 'liewitnesses' claim sudden changes in direction, they are using their
>stationary reference. Anyone experienced in air operations of tactical
>or other high performance aerobatic aircraft know that this perception is
>because the people are ignoring changes in distance. To the observer, a
>travelling across one's field of view will seem to come to a rapid stop and
>hover, then zoom off in another direction, when in actuality they are
>a turn where the midpoint of the turn is when the plane is either moving
>or away from the observer, so it just seems to hover. Whenever I hear of a
>report that includes 'rapid changes in direction', I know what is actually
>on, and that the eyewitness is ignorant of flight dynamics, and lacks an
>to think in three dimensions. Note that people have poor depth perception at
Quite true in a great many cases, but there is a body of close-range reports and other, videotaped reports, that indicate that we might be dealing with a truly exotic propulsion system. There have been a handful of mass-sighting reports when the object under question was seen by many only at certain angles; to all intents and purposes, it was "invisible" to other witnesses who saw the object reappear shortly after.
There's a meme running through the UFO counterculture that describes this as the effect of gravitational warping. Theoretically, UFOs distort spacetime in order to fly, using gravitational lenses to focus on a particular point, which they _draw toward them_. This way, there is no contradiction with physical laws; the UFOs aren't even really "flying," per se.