Unsealed Alien Files S03E10 Antigravity

UFOs. They can fly at blinding speed or hover effortlessly just a few feet above the ground. And they can do it all without making a sound. How is this possible? Many experts believe the answer is anti-gravity propulsion-advanced technology capable of controlling one of the most powerful forces in the universe. And some believe this gift is no longer exclusive to extraterrestrials. Is it true?