People ought not to confuse speculation and fiction with real science. Yet on opinion boards speculation and postulation to advance a narrative or agenda is to be expected and is half the fun. Still it would be interesting if a credible journalist or investigator polled and questioned the Chairmen of the Department of Physics from America’s 100 top research universities and asked the question. What is the true likelihood that UFOs are indeed mechanical and biological entities that originated from planets many lightyears away. Or is there another more likely explanation to explain the visual observations of many pilots, most of which BTW are not detected on radar.
That is like presuming they must walk on two legs, breathe air, and eat plant or animal matter for sustenance.
Despite whatever the chairman of a university department of physics might say, that is narrow-minded, uncreative, trapped-inside-the-box thinking.
Despite the fact that humans have invented the iphone, the jet airplane, and the electric car, we are by all objective standards still a primitive life form. We haven't even developed a cure for male pattern baldness or the common cold.;-)
For us to point to our current "facts" as a determinant for things we have yet to discover or encounter is like listen to Lord Kelvin lecture us on the impossibility of video conferencing.
In all due respect, you are thinking like an accountant.
If they were legit scientist, all of them would say somewhere between 0 and 100. Some closer to 100, some not. None would say 0, and none would say 100. ;)
Is it possible? Yes. Is it probable? No one on this earth knows for certain. There is plenty in this vast universe that we know very little to nothing about. But to say it is indeed 100% impossible is to know 100% of everything within and about the universe.