This report [http://lesswrong.com/lw/1s4/open_thread_february_2010_part_2/1n29] makes it seem like UFO sightings of the kind Jayson experienced are relatively common.

And a memo reveals how former prime minister Winston Churchill expressed curiosity in "flying saucers" and requested a briefing from his ministers.

He was told in reply that following an intelligence study conducted in 1951, the "flying saucers" could be explained by "one or other" of four causes.

These were known astronomical or meteorological phenomena, mistaken identification of conventional aircraft, optical illusions and psychological delusions, or deliberate hoaxes.

The reports on objects previously known as UFOs would probably be more interesting.