Assertion: ufo | /r/HasProperty | airborne object
Facets:
Source sentences:
text: In its initial definition, the USAF stated that a UFO was: "Any airborne object which by performance, aerodynamic characteristics, or unusual features, does not conform to any presently known aircraft or missile type, or which cannot be positively identified as a familiar object.
text: In principle, there's nothing wrong with the airforce's definition except that not all UFOs are actually "airborne objects" (see below).
text: The U.S. Air Force adopted a similar official definition in 1954, saying a UFO is "any airborne object which by performance, aerodynamic characteristics, or unusual features, does not conform to any presently known aircraft or missile type, or which cannot be positively identified as a familiar object.