This is a quite stupid question that keeps getting muddled. Of course UFOs are real, but that is not the problem. The real problem is with the “U,” that is they are unidentified.
Many people, apparently, want these UFOs to be evidence of visitations from extraterrestrials, i.e. real aliens. That interpretation is still open.
So, UFOs are real. They are real mistaken identities, real secret weapons systems, and real we don’t know what the heck they are. But what about the aliens? Most people are ignorant of basic science, so allow me to establish some parameters based upon known scientific limits. One of those limits is that as a physical object, such as a spacecraft approaches the speed of light, really any sizable fraction of it, the amount of energy needed to increase the object’s speed goes up, well astronomically. This makes moving a space craft along at the speed of light essentially impossible, but let’s assume, for the sake of this discussion, that such a feat, travel at the speed of light, were possible.
If any neighbor of ours wanted to come our way, what do you think would be a reasonable travel distance? I suggest a reasonable limit to that distance is 100 light years. If a planet is 100 light years away (the distance light were to travel in 100 years) and it had a spacecraft capable of doing what we think impossible, traveling at the speed of light, they would be undertaking a trip that would take 100 years to get here and 100 years to get back. Even if these space faring aliens lived incredibly long lives, that is a very long time to be cooped up in a spacecraft, exposed to the hazards of space travel (nasty radiation that cannot be blocked out, the vacuum of space, tiny meteoroids that can and do punch holes through spacecraft, no refueling/reprovisioning stations along the way so you have to bring everything with you, etc.). The boredom alone would make the trip daunting.
So, there is a region in space surrounding our planet, that is 100 light years in radius from which we could reasonably expect a possible visit. How does this compare with the size of the rest of the universe? The universe is 14 billion or so years old, so its radius is about 14 billion light years. To compare the volumes, we need to cube the radii of both “spheres” and we end up with a ratio of 1003 to 14,000,000,0003. That means our little neighborhood constitutes roughly 3.6 x 10–23 of one percent of the entire universe (just add a decimal point and 22 zeros in front of the 3 and you can drop the rest).
We could conclude, therefore, that our little bubble in space also contains that fraction of the space faring intelligent alien species in the universe, too. Oh.
If you have ever wondered why we don’t see “them,” this is why.
Oh, I didn’t mention the time problem. The universe is 14 billion years old and we have been looking for aliens for maybe 100 years … to make a long story short, we have a similar fraction of time in which such encounters could occur. Space faring aliens may have come and gone, too far away to make contact, millions of times and we couldn’t possibly have noticed them as we were not looking.
There is a reason why science fiction authors are constantly inventing methods of travel (wormholes, warp drives (whatever that is), etc.). The inventor of the warp drive was cagey enough to not define what a warp number meant. Most people think it is like the Mach system with the speed of light replacing the speed of sound, so Warp 5 is five times the speed of light. The Star Trek shows seem to indicate that a limit to their technology was travel at about Warp 10. If this actually represents ten times the speed of light, then that expands our bubble 1000 fold! Hooray! Which brings our percent of the universe within reasonable travel times to 3.6 x 10–20 of one percent. Oh.
If you happen to be a theist and are wondering why a creator god would have created so much of the universe inaccessible to us, you may want to consider that he wanted to keep all of his created creatures separated for a reason (maybe until we learn that Kill, kill, kill! is not a good first response to anything strange), or maybe he enjoys a good joke, or maybe he is just perverse, or….