They're invading... watch out!!! ohhh nooooo!!!!!!!!!!!!!
Well, it's in the sky so I guess it is OK to assume it is flying. Mr. Anonymous doesn't know what it is, so it is unidentified. Does that clear it up for you?
I would think at the end, when it lands at the nearby airport, Mr. Anonymous might pick up a clue as to its identity, but who am I to judge him?
you know... it is a UFO - I always forget about what it actually stands for - I just think alien ;)