Why do some people think UFO's do not exist simply Because "Aliens do not exist"?

UFOs are more associated with extraterrestrial spacecrafts thanks to the media and pop culture especially with shows like the X-Files even though it's defined as any unidentified object that's flying, hence Unidentified Flying Object.

As to sayings not existing, that's extremely arrogant presumption to think we are the only intelligent life in the universe.

Naturally the Fermi paradox asks where are they? Because we should have heard from them by now.

Should we?

We have to be at just the right distance and they have to be advanced enough but not too advanced to send a signal at just the right time in an extremely improbable scenario to receive their signal.

As to getting here even our physics says it's not impossible especially with theoretical concepts like the Alcubierre warp drive.

The idea of ET visits is hard to believe, but the word is believe. And scepticism is a belief, not a science.

This is a really important question because so much to learn from a simple experiment. When the three boats in Columbus' armada sailed, and first appeared on the horizon to the Native Americans, the tribesmen did not SEE. Their belief in values only set themselves outside the possible existence of sailing ships. So they stared for long hours as the ships travelled closer and closer. Then they called the medicine man, the "shaman" man or woman. Etc. But for UFO's we think we know. We don't know what we are seeing. We can call it "alien space ship" but we don't know aliens or how long they have been traveling, or where in the galaxy they could have come. Our brains still can not fathom what is before our eyes. It is an overwhelming faculty of fear, to protect us from that we live in ignorance, and direct all questions and prayers to the sky.

Religious beliefs of Individuals on here.

The problem is travelling faster than the speed of light, Einstein thought it couldn't be done, and that means in order for them to get to us, given that we can't see any evidence of large settlements of intelligent living creatures with space ships in our solar system, would take thousands of years, unless they found some way of going faster than light, which may be possible, it's just very unlikely seeming. Then again, it's very unlikely that we exist at all, and my personal belief is that the universe moves in an eternal cycle, the big bounce theory, meaning all possible variations happen an infinite amount of times. This means if it was possible to escape the big crunch and resulting big bang in a space ship, and continue on like that through multiple cycles, collecting more fuel in each new universe, then that would have been done, in fact, done an infinite amount of times, so perhaps there is a race of almost infinitely old and unimaginably intelligent space creatures, although it's likely that genetic flaws would wipe them out eventually, or something. They would have to put themselves in stasis, some sort of quantum sleep in order to survive long journeys in the same generation, unless they were somehow able to defeat death. This is all very much speculation, as is most of the stuff in this area. You could say people saw this or that, but people also saw ten thousand "gods" and angels and demons as well.

The last time that UFO meant extraterrestrial space craft was never. it just means unidentified by the people who saw an object.

Here's where I bust your assumptions.

Aliens do not visit because:

There are very few of them capable of getting anything into space. Why is that? Because they don't have the technology or their planet is too dense. This means that on average that aliens who do exist AND are able to get something into space are few and far between. So on average they are very far away, maybe thousands or tens of thousands of light years.

In addition even if they do send out probes they do not have to come this way, they can go in any direction at all. Most likely they do not know we exist and radio is no help, since it fades below the interstellar noise in a few hundred light years. Yes we get very very faint signals from distant galaxies, where the transmitter is the entire galaxy broadcasting on billions of watts and that takes hours for a huge radio telescope to collect enough signal to make sense. A transmitter made by aliens or humans will be thousands of times weaker.

And what if physicists are right and the speed of light is really a limit? That means that aliens that do live relatively close would spend many hundreds of years in a tin can in space. Maybe they do not like that idea. Would you?

of course aliens exist - they illegally cross into the US daily

Obviously UFOs exist.

The acronym UFO means Unidentified Flying Object NOT flying saucers.

This means that anything flying across our skies that cannot be identified by conventional means are classed as UFOs.

No one on this Earth can say aliens do not exist because no one actually knows but I am sure that this Universe is teeming with life and that must be a mathematical certainty when we consider the billions of Galaxies and the billions of Stars, the trillions of Planets and Moons orbiting those Stars.

Poseidon

I don't know about "some people" but both exist, and have nothing to do with each other.

If aliens didn't exist, who would build the UFOs?

I think if you were to press them, they’d admit they were equating the term “UFO” to “Alien Vehicle”; UFOs certainly exist - anytime someone doesn’t know what they’re seeing in the sky, that’s a UFO... it doesn’t mean it’s alien, just unidentified.