If you really do your homework, you will discover that the period when these discs first appear is the early 1940's and that credible people have determined the Germans were on to something beyond Newtonian Physics.
The first official sighting is claimed by two Navy Intelligence pilots over Washington State in 1947 and it's no coincidence that thousands of German scientists were spirited to safety after the war.
Obviously your mind is probably made up, and you wouldn't be investigating the phenomenon if you didn't have strong feelings about it. But before you dismiss me as a nut, read "The Hunt For Zero Point" by Nick Cook, aviation editor of Jane's Defense Weekly. Watch a TLC program called "The Billion Dollar Secret". These two sources will give you a good idea of what your seeing; a craft powered by a gravitational field that literally 'falls' in whatever direction the pilot steers. Another field inside the craft protects the occupant from G's that would kill anyone making a turn like the ones typically witnessed.
There's plenty of other source material, more than half mixed with fabrication and truth, including this video. The music is so cheesy and the production value so low that it is really not worth the price, however as I said, there is sadly a grain or two of truth here.