I don’t believe that the two — alien life and UFOs — are synonymous. Alien life off-planet, sure, but here? Probably not, at least not “here” in a sense we’d recognize. I think UFOs, though, are simply the modern-day version of the mysterious things humankind has seen through the ages, including things like faeries and dragons, and probably fiery chariots, etc. I suspect there’s some phenomenon that some people can sometimes sense, something that’s physically real but difficult to easily detect. Over time our explanations for what we’re glimpsing have changed, but the phenomenon is no less real. Doesn’t mean UFOs are aliens, therefor.