Yes. It means someone saw something they can't identify. But it's not like finding a four-leaf clover or walking under a ladder. There is no superstition attached to it.
They usually see UFO's at a UFO sighting
Yes.
James (Jimmy) Carter, who was the governor of Georgia at the time he reported the sighting.
On March 24, 2011, over Southhampton, England, a triangular, black UFO sighting in broad daylight.
The first actual UFO sighting was in 1500 B.C.!
Yes there has been a UFO sighting in Egypt.
yes
That was prior to written history so there is no record of the first sighting.
Today. Nearly every day there is a UFO sighting. It is a global phenomenon.
No UFO sighting was reported in AD 961...
No UFO sighting was reported in AD 962...
No UFO sighting was reported in AD 963...