Are the secretive files of UFO's actually human made air crafts being hidden from the united states of America's public?

I have a question directed to the president and CIA. Their are documents being hidden from the American public, supposedly in hangar 1, but I am curious and determined to find the answer to my question. I honestly don't trust the government enough to trust any reply you may say, but I believe UFO's that have been spotted and documented are human made, probably by the U.S air force, CIA, or some new branch of research. My precise question is, what exactly are the UFO's being hidden from the U.S public and what are their purpose? I believe they are being tested and planned to use for stealth to spy or attack, but can't be released to the public because it may leak to other countries or certain people they are trying to hide this from.