Five Good Reasons To Believe in UFOs

The aliens came, studied us, and left, deducing there was no intelligent life forms on Earth.

This could be tagged by humor, science fiction and space exploration SPC Robert Coventry.
Unidentified flying objects have been around since soon after the Wright brothers launched their biplane from Kill Devil Hills in North Carolina.
Many flying objects have been unidentified especially during warfare and strategic tracking aircraft which try to avoid being detected.
Just because some UFO is unidentified does not make it logical to be something from an extraterrestrial origin. Of course our imaginations love to conjure up explanations that are farfetched :-)
summary critique
1 • The long, documented history of sightings. UFOs were around, in fact, long before humans themselves took to the air. [Before high speed cameras to record events it is difficult to verify. Mass hallucinations due to ergot poisoning and other deliberate attempts to get high through opium and cocaine in the 16th through 19th centuries produced many interesting ideas :-)
2 • Numerous modern sightings by credible, well-trained professional observers. In Ruppelt’s 1955 book , “The Report on Unidentified Flying Objects,” he documented numerous instances of military service members, military and civilian pilots, scientists and other credible professionals who had observed UFOs. [Storm chasers have a legitimate function and operate in reality albeit a dangerous one. Those search and focused on UFOs like ghost hunters will tend to see evidence through a biased lenses unless they are very careful. :-)
3 • Consistencies in the descriptions of purported alien ships. Over the decades, witnesses who’ve seen UFOs have shown remarkable consistency in the shapes and other characteristics of the objects they’ve described. [At least the phrase purported alien ships is used. Commonality of design in craft which fly as heavier than air objects is akin to commonality of design in animal and plant life - four feet are stable [three would be more but would be ungainly for a number of reasons :-)
4 • Possible physical evidence of encounters with alien spacecraft. [many human-generated technologies are sensitive or classified before they are mainstreamed and some will never be. Unexplained evidence without a need-to-know makes for entertaining but non-factual explanations :-)
5 • Physiological effects on UFO witnesses. [PTSD and similar trauma does not prove a causality which is extraterrestrial origin.]
FYI COL Mikel J. Burroughs LTC Stephen C. Capt Seid Waddell Capt Tom Brown SFC William Farrell SSgt Robert Marx Maj Marty Hogan PO1 William "Chip" Nagel SPC Margaret Higgins MSgt Jason McClish AN Christopher Crayne LTC Bill Koski SPC Tom DeSmet SGT Charles H. Hawes LTC Wayne Brandon SGT (Join to see) SGT Michael Thorin SGT (Join to see)

Just believing we're not the only intelligent lifeforms in a vast universe is enough for me.