In the statement that says they “are not currently within the U.S. inventory nor in any foreign inventory that we are aware of,” it says the foreign inventory is not fully known. That opens up the possibility of a ongoing top secret program used to monitor activity in the United States. When these spy craft appear in U.S. skies, people think they are from another planet. This type of spying goes on among several nations. It’s just that no one wants to tell about it and would rather let people blame it on the myth of extra terrestrial beings checking out us earthlings.
The emerging surmise by many UFO researchers is that most UFOs are from alternate dimensions, from an advanced hidden civilization long resident on the planet, or from a future, advanced version of mankind. While the small size of the objects observed by the USN argues against their being from a distant alien civilization, it does not of necessity indicate a mundane origin in contemporary military technology.