So, it looks like, since long time ago, that we have to pass from a dispute of advanced technological flying objects' existance to a search for their origins and source.
In other words, from where they come from, who or what holds such kind of advance technology? An extraterrestrial civilisation/force perhaps? Is it a secret project of U.S goverment to control the world? Maybe an ancient tribe's effort to reconquer the world from a subterranean lost continent or from planet Mars? A visit of historical interest from the mankind of future.