Given what I've read about UFOs, I'd bet money on the notion that we don't know so much about esoteric physics. By the way, I majored in physics.
Even Albert Einstein said, "Knowledge is the measure of the radius of the Sphere of Ignorance". He also said, "Imagination is more important than knowledge". Another interesting statement, "The only thing that interferes with my learning is my education".
If would be silly and arrogant to assume that we have mastered the Cosmos. We can't even get income tax correct.
True but my point still stands. Between the USA, Canada, USSR and China there was a lot of land mass for an alien spacecraft to come down in or even to crash in. None of those governments seem too interested in funding research into what you refered to as esoteric physics.