You need proof? I have none. All I can say is that on about 10 occasions over my lifetime I have seen strange things in the sky. On three occasions, there is absolutely no doubt what I was seeing were real UFO's. And if you saw what I saw, you would think so too. The other day I was watching some UFO program. They were talking about various reasons why the government doesn't admit that we are being visited by beings from other solar systems. Nobody has ever given the right answer. The real reason is that there is one thing that those in government love above all other things. Power.
For example, most people will seek to be in a position of authority. I saw a couple things on TV where they had part of a bus stop roped off with some of those velvet ropes. The area within was for "special" people. There were people who were willing to pay extra to stand within those ropes so they could feel superior. I also saw the same thing done in a section of a laundromat. People would pay extra to stand in the roped off section.
Just imagine if the government let it be known that we were being visited by far older and advanced beings from another star system. That would knock any superiority from their position they might feel down by a peg or a couple dozen. And most people would probably think, "Why should I listen to you. You are less than a cave man compared to those other beings." As for the advanced beings themselves, they would have no reason to make themselves known to the general public. For one reason, whether or not we survive as a species is something we need to accomplish for ourselves. Nature will weed out the unfit.
Also, if they made themselves known to us, No doubt they would be pestered endlessly as to what we should do. I'm sure they have better things to do. And even if they did, most of the humans probably wouldn't like the answer. And should they survive, they would always view the advanced beings as enemies. Another thing is that most humans only want things to be one way. Their way.