http://truthufo.blogspot.com/

An Unidentified Flying Object, or UFO, is the popular term for any aerial phenomenon that cannot immediately be identified. Some definitions, such as the one used by the USAF, define a UFO as an object unable to be identified after scrutiny, while other definitions define an object as being a UFO from the time it is first reported as being unidentified, even though most subsequently become IFOs, Identified Flying Objects.