I don't know enough about these craft known as TR-3B to make extended comments on them except to say that every single source I've encountered says the black triangular craft belong to the either the US military or the shadow government structures. Richard Dolan has coined a term for them. A breakaway civilisation.
The music accompanying this video is sufficiently polished enough to ask the question, what's the motivation of the maker? But it's also good enough to post and say take a look, enjoy and go do your own homework. Suppressed technology is a logical outgrowth of capitalism if you really really think about how power and money works. There's no dough in releasing oil busting technologies to the people. There's no money in a cure for cancer either. Greed is also something people might be more acquainted with.