Let’s use math & facts to resolve the UFO/alien issue once & for all, assuming you won’t deny the basic facts . . .

Our fastest manned spacecraft (forget smaller probes — we have to transport people/aliens here & protect them, so we need something bigger & more complex) can only travel 25,000 mph tops, as Apollo 10 did when it set the record in 1969.

The nearest planet (which is not hospitable to life as we know it) is appx 25 trillion miles away, which is appx 4.3 light years.  A light year is how long it takes light to travel in a year going 186,000 miles per SECOND (not mph), which appx 670 Million miles per hour (mph) x 24 hrs = appx 16 Billion miles per day x 365 days = appx 5.87 Trillion miles in a year.

So it would take a manned spacecraft traveling to the nearest planet appx 114,000 years to get there at 25,000 mph going appx 25 trillion miles.

Logic tells us that any other civilization like ours would probably have the same constraints we have in travel & technology as most planets would probably have the same chemicals/elements we have, but even if they figured out how to travel 100 times faster, and assuming the nearest planet was indeed hospitable to intelligent life (we believe the nearest one is actually 12 light years away, or 3 times as far), it would still take them 1,140 years to travel here (3,420 years to the nearest Earth-like planet), and if they are lifeforms that require food & water & are susceptible to harm from typical space travel (as most all life is), it would not be able to store enough food & water to make it here or acquire it in space.

In other words, theoretically, there are no space aliens coming here as they can’t physically do it, and all the UFO’s we see are of this world & usually man-made, or are meteors or light phenomena.