Btw I do not know how deep into the rabbit hole you are comfortable going but I believe that the flying saucers were hidden but I do not believe they all were non-human in origin.
Richard Dolan knows about the other alternative but he does not discuss them in this particular video.
The other alternative can be found discussed on his and other sites with terms like “Breakaway Civilization” or “Secret Space Program”.
Dolan himself created the term “Breakaway Civilization”.
The full deep rabbit hole (if you want to go there) is explained in this four hour video “Introduction to the Secret Space Program”.
https://www.youtube.com/watch?v=t564HRXeS6o
Don’t be intimidated by the length.
You can watch it a few minutes at a time to get the gist of it—and they have Powerpoint slides that show the topics they are discussing.
It is like studying a brand new subject—new terms, new people, new history—a lot to take in. If you can avoid rushing to judgement and just try to understand what they are saying the rewards will be great.
I think it is mostly legit—but of course most folks do not share that view.