I always laugh at the concept UFO, my reasons:
Unidentified, is only the case if you don't know what your looking at, so your pereption of whats seen in the sky might differ from mine purely because I've drawn my own conclusion.
(therefore Identified)
Flying, people always suggest it's an object flying, but what makes them so sure it's an object at all?. In certain respects it an be many things, like the matricing of dopplers from multiple antennas to cause radar ghosts for the military usage of illusion.
(Afterall you could make a whole squad appear on radar, that are no more than just a field of Electromagnetics and static ball lightening. Meanwhile stealth craft appear elsewhere with the enemy fighters scrambled somewhere else.)
This puts forwards that the EM ball isn't flying, it's just flowing frequencies matriced at one point.
And that pretty much covers how it might not be an object.
So in all due respects, UFO's don't exist. (And this is why Governments can truthfully state this)