A key characteristic of a UFO is that it is an unidentified flying object. Describing something as a UFO doesn’t necessarily mean that it is an alien spaceship or a psychic phenomenon, it simply means that it has not (yet) been identified.

The vast majortiy of UFOs sightings turn out to have a very ordinary explanation. In this case the sighting is reclassified as an IFO: an identified flying object.

Some of the most common forms of IFO responsible for UFO reports include (in no particular order):

  • Bright planets
  • Meteorites
  • The moon
  • Aircraft
  • Satellite re-entry
  • Balloons
  • Blimps
  • Laser light displays
  • Wedding lanterns (fire balloons)
  • Birds

A new addition to the list is the launch of Starlink satellites by Elon Musk’s SpaceX. These have resulted in reports of a string of lights in the sky travelling in a line like train carriages.

It’s important to remember that although the vast number of UFO reports turn into IFOs like the ones listed above, a stubborn minority refuse any conventional explanation and remain a mystery. Those who seek to debunk the entire UFO field often focus on the IFOs and brush off the unexplained sightings as hoax, error or delusion.