I know they exist, but the question is who is piloting them?How do I know? I read books on how to build a flying saucer or a spacecraft. I have learned that the reason why they keep on denying the existence of UFOs is because if they were accepted as real things, the entire structure of education, science, politics, transportation, oil industry, and the fiction based government we believed to be the good guys, would all crumble at our feet. That is the reason why they don't talk about it even when a higher-up in the government system opens a case asking "What the HELL flew right in front of MY plane!?"There was a German scientist that found ways to recreate the UFO way of propulsion. By the use of gravity, which can be done in anyone's backyard, the object is able to go in and out of planet atmosphere's like nothing, move so fast that it would make the latest spy plane look like nothing, and no matter how big it is, it's still going to go faster than 1000 miles per hour.This all begins with the accepting the idea of that gravity is just an EM force that operates at 1 terahertz.However, if we can build crafts like these, then we can also bring them down with no problem. If they run on electricity, then a simple EMP bomb or gun would do the job, or just get a cloud-buster and point at the craft and next thing you know, it's down.