Do you think aliens in ufos have visited Earth? (And all things UFO)

I mean, it would make sense to suppress a story of this size. Mid to late 1940's, you start hearing about Aliens, roswell, etc. The world was just getting out of the most horrible war ever waged in human civilization. Imagine coming clean you found something unexplained, not from this world and is so far advanced that you can't even fathom where its from, then you went and showed it publicly? Keep in mind, this is at a time where the Russians and the USA were quietly pilfering remaining German engineers and scientists away secretly to further weapons research and development.

Fast forward to today, there is a tremendous amount of real fear to reveal something of this magnitude for all to see. Imagine for a second these are emotional beings from another place, once the intriguing period of it all settles, what happens if you make them mad? They can already transcend entire galaxies with their technology, I don't even wanna think about the kinda weapons they'd possess.