Stay with the facts on this one
It is also factual that at 10 pm the military scrambled some jets that dropped flares around 10:30 pm to cover up the UFO event. This has been clearly documented.
So now we have two entirely separate events happening, the first one is a bona-fide UFO sighting and the second is an obvious attempt to cover that sighting up. The military effort was too little too late so the UFO sighting stands.
So when you boil this down to what we actually know it comes down to the following. Either the American military have advanced craft beyond our wildest imagination or they have been dealing with extraterrestrials for a very long time.
So now you get into a few questionable areas, if this is a military experimental aircraft, who built it, after all it is almost one mile in length. It would have taken so many people to build and work on that it would be close to impossible for them to keep it secret. Second, lets keep assuming this is a military craft, where do your park a mile long craft. It would have to be underground or at some amazing facility with beyond state of the art camouflage abilities. A third possibility is that this craft can remain right out in the open and it has some type of cloaking device. These three scenarios are all possible but you have to admit highly unlikely. That leaves only one more plausible explanation, an alien craft with advanced beings visiting planet earth and in particular visiting the American Military.
Then there is the question why was it seen over Arizona that night, again it boils down to one of two reasons, 1) it was intentional, to prepare the world for disclosure, 2) it was some sort of malfunction and it was never meant to be seen and certainly not at a low altitude by so many people.