They cannot be hidden if they do not exist. The first UFO reports were made by Kenneth Arnold, a private light aircraft pilot back about 1947. He reported crescent shaped objects below his plane skipping along like saucers.
A news reporter got it wrong and the name "flying saucers" was born. For years afterward there were reports and stories about flying saucers, even photographs, some of which were identified as car hub caps. Mr Arnold must have been amused that these supposed saucers were nothing like what he saw, or claimed to see.
And not just in the USA, reports came in from dozens of countries. Now perhaps the US government is interfering in the internal affairs of all these countries to the extent that they hide the UFOs spotted in Britain, France, Germany, Australia , Russia, Argentina etc from the public in those countries or the governments of those countries are also hiding UFA and aliens. In the 68 or so years since Mr. Arnold's report, governments in various countries have been competent or incompetent.
They have changed by elections, revolutions, coups etc and no convincing records have emerged from any country of any UFO's or aliens. So either hiding of these things is tremendously effective or they do not exist.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.