Contrary to conventional wisdom, people of all levels of education like to believe in "weird things," says Michael Shermer of the Skeptical Inquirer. Shermer wrote that people tend to seek or interpret evidence favorable to existing beliefs and ignore or misinterpret evidence unfavorable to those beliefs.
This is no more obvious than in the writings of "creationist scientists" who either reject or grossly misinterpret geological, biological and astronomical data to support their biblical-based belief in an 8,000 year-old universe.
This "confirmation bias" is in real science as well. The classic example is the 1903 discovery of "N-rays" a completely new form of radiation announced by Prosper-René Blondlot. At the time, dozens of other scientists confirmed the existence of N-rays in their own laboratories. But further tests showed that N-rays don't exist at all.
How could so many scientists be wrong? They deceived themselves into thinking they were seeing something with their instruments that in fact was not there. This came on the heels of Wilhelm Rontgen's discovery of X-rays and Paul Ulrich Villard's discovery of gamma rays in the early 1900s. Apparently there was a predisposition to expecting that other invisible forms of radiation must permeate the universe.
Likewise, any two people can see a blob of light in the sky, one thinking it is the planet Venus and the other person predisposed to interpreting it as a space vehicle under alien control. Yes, airline pilots, and law enforcement office seen strange things in the heavens too. But this is outside of their sphere of expertise - especially when it comes to astronomical phenomena seen under unusual conditions.
Collectively, UFO stories are a sci-fi inspired projection of how we think space visitors would look and behave. Despite over 60 years of "sightings," the purported scientific evidence is largely anecdotal and uncorroborated. The Mars Science Lab landing left more physical evidence strewn on the Red Planet than thousands of alleged flying saucers reported over the decades.
I'd say that UFO beliefs are fueled by a "secular theology" where people look for greater meaning to the universe and our relationship with it. The theme is that the aliens flying the UFOs pay attention to us, worry about our misdeeds (as evident in alleged sighting of UFOs hanging around nuclear power plants) and want to help raise us to a higher level of existence. This is simply a post-industrial age version of ages old stores of visitation by angels, demons, and other imaginary spirits.