Like The X Files, Project UFO dealt with sightings of alleged interstellar travelers. That, however, is where the similarity ends. While X Files was pure sci-fi, and heavy on emotion, Project UFO was actually fact based, if somewhat loosely. The episodes were taken from the files of Operation Blue Book, the Air Force investigations of strange sightings in the sky. This was stopped in, I think, 1968.
As in real life, most of the sightings in the episodes were explained as earthly phenomena. But not all. I haven't seen it since it's original NBC run in the late '70s, but I do remember one episode that ended with a strange intelligent creature communicating with a little boy, explaining the creatures journey to Earth and telling the boy not to be frightened.
It was produced by Jack Webb's Mark VII Productions, adding an extra air of credibility, something The X Files lacked. I don't recall if it has aired since its original run, but it should. I think Sci-Fi could find room for it, and I believe there would be an audience for it, even though it was relatively short lived. A complete series DVD set might find a market too.
In answer to reported UFO sightings, the United States Air Force began Project Blue Book, an investigation which attempted to determine whether or not these sightings were really extraterrestrial craft and, if so, whether or not they posed a thread to U.S. national security. Created by Dragnet Star Jack Webb, Project UFO was a sci-fi drama based upon the real life investigation and reportedly used the actual Project Bluebook files for story ideas.
I saw Project UFO as a kid and as I recall this show was a lot like some of the other shows Jack Webb was involved in, real to life and focused upon the less glamorous side of being an investigator. Although the sequences that showed the UFOs were well produced and featured great model work, the show's subject was the investigation, complete with dramatized interiews, scientific reasearch and the kind of real-life footwork that investigators do every day.
Of course the investigators would generally debunk the UFO in question as something other than an extra terrestrial craft, but often the final act would feature the same UFO in a different setting which would lead the viewer to question whether or not the investigator's determination were correct. Thus, Believers were allowed to continue believing and doubters were allowed to doubt.
This was an OK show, but like a lot of science fiction based shows in the 70s, it never really found a strong audience and did not last long. I think that might have found a following if cable TV had been commonplace when it was produced but back in the day two seasons was a pretty good run for a show like this.