All things being equal, the simplest answer is usually the correct one.
Are you saying that the simplest answer to unexplained lights in the sky is that we are being visited by an advanced species from a different planet and that some people, large groups of people, are fully aware of that fact but that the general public has been kept in the dark for at least 60 years now?
To me this is a case where we do not need a complete answer all at once. Take what we know about unexplained phenomenon and examine it without preconceived notions about what it means and let it take you where it may.