We have fired on UFOs many times or at least attempted to, and I knew that decades ago. We have many cases on record of UFOs being chased and acting in a very evasive manner, speeding up and outmaneuvering our planes. That much is easy to prove based on the declassified records.
Whether we ever had anything that could shoot them down is another story. I have said many times that we have lost planes and pilots trying to do so.