No, they would not tell us. Panic is the last thing they need. What they would do, however, is slowly get us believing in these things until one day it just became common knowledge. Probably around the same time we saw them as a threat to our world!

No, the US releases no information on UFO's except misinformation.

If they had the chance they would probably try. Sole possession of that sort of technology would be irrestible. But frankly the government is terrible at keeping secrets and moving a UFO to a secure sight would likely take a lot of people to accomplish. People blab. The intelligence services of other nations would very likely learn of its existence. That would cause a major diplomatic problem and could cause potential military action. No nation, given a chance, could allow another nation to gain that sort of advantage. And any possible war to gain control over the technology might be foolish. There is no reason to believe that we could understand or duplicate alien technology. Imagine an F22 in the hands of the US government in 1860. They would have no conception what it was, how it operated or anything about the electronics. The very concept of electronics hadn't been invented and there were no aircraft that early. And that is only a technological difference of 150 years. In terms of technological development that is nothing. An interstellar capable civilization would probably be thousands of years more advanced than we are. There is little likelyhood we could ever make any use of such technology.

I do not think the USA government is competent to hide much from us.

Why would they tell now???They have been hiding the evidence since 1947.