Unidentified by whom though? If a remote tribe of hunter-gatherers sees a helicopter for the first time, it is an object and it is flying and it is unidentified (by them,) but it’s not a “UFO.”
The official USAF definition was initially “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.” This was later amended/clarified to include only those objects which remained unidentified after an investigation.
So it’s not as simple as “I don’t know what that thing is therefore it’s a UFO.”
