UFO sightings over nuclear facilities trigger high alert responses - are they top-secret aircraft or something from another world?

An investigation into triangular-shaped UFOs seen in the 1980s and 90s - they might be the best evidence of extraterrestrial crafts?

Well-documented sightings of UFOs by commercial airliner pilots may be proof of danger lurking in our skies.

True stories of fighter pilot encounters with unidentified flying objects in our skies – including pilots who were ordered to ‘shoot ‘em down’.