I wanted to add a bit more to this answer. Governments around the world do have some sort of running agreements/covenants with "aliens" and it did not start after WW2 as they try to make believe. Contact was made much earlier than than. What do you thing most religions are? They are just a a form of cargo cult behaviour that is manifested in lower cultures when they come into contact with highly advanced ones. Also were do you think the mentality of predestenation of the Jews came from, i.e. being the chosen. In simple terms they were contacted by aliens, tinkered with genetically, made them believe they were chosen because they were special unlike their enemies.
In the meantime the same group of alien *****ers when realising that maybe the neanderthal stock of ancient jew genetics weren't all that good for their purposes, started tinkering with other races, or maybe they just did it to divide and conquer. The jews being envious little *****ers got jealous of this and adopted a whole religious belief whereby all the other races are just evil empty remnants of the vessel that "contained god" and exist by sucking the energy of jew souls that are the real pieces of the splintered "image of god"....bla bla bla. Basically the jews are morons that don't want to admit they were double crossed by inter-dimensional pirates that have manipulated them into becoming the scapegoats of the world to steer the pot for a specific goal they have. It is a running experiment which is still on going till this point. All this may sound far-fetched but masonry and Mormonism, which are crypto-jewish parallels, all clearly recount how mankind was approached by aliens at some point.