I think the notion that we will somebody prove that UFOs are real is a bit silly. I do not think that we will ever be able to prove that UFOs are real because of all the different factors that go into their reporting. First of all a lot of the people who claim to see them are not trust worthy.
The grey area involved with describing what a UFO is, and the difficulty in providing tangible evidence makes it unlikely that UFOs will be proven to be real. This sort of gets at the question of if a person believes aliens might exist, and in my case the answer is no, or at least they don't care to come spook people on earth.
Philip J. Klass' assertion will continue to hold true as there has been no evidence of any extraterrestrial life yet discovered neither here nor beyond earth. Therefore, due to this complete lack of evidence, there remains no basis for proving any supposed UFO as real. The science of astronomy has thus far not found any other planets beyond earth holding any potential to sustain extraterrestrial life either.
People see all of the so called evidence of UFOs and immediately try and apply this to history. In reality, there is little actually evidence other than for a small amount of time between the 40s and the 70s. Ultimately, considering that everybody today has a camera in their pocket, it seems odd that there isn't more proof if they were real.
The Tinley Park case proves that UFOs are already real, UFOs are unidentified flying objects. They Tinly Park Object was just that. We know it existed because it was caught on tape by hundreds and was proven not to be flares attached to weather balloons. So they weren't flares, they weren't airplanes, they weren't swamp gas, they weren't natural, they weren't conventional, so they remain unidentified. The only explanations we have then are, they are top secret military technology, Extraterrestrials, or Interdimensionals, or intraterrestrials, so UFOs are already proven to exist
and Philip Klass was a liar working for the CIA
If UFOs can never be proven real, the opposite is true. They can't be proven false, either. Sure, many of the occurrences have rational explanations, but some do not. They are still mysteries that defy explanation. Most scientists also agree that life in outer space is not a statistical probability., How can we say we have not been observed or visited?