Because the F stands for “flying” in the acronym UFO, it stands to reason that pilots should frequently be UFO witnesses. They certainly are and there is even a specialized reporting center just for them. The National Aviation Reporting Center on Anomalous Phenomena was founded in 1999 by Dr. Richard M. Haines. The organization is dedicated to the study of Unidentified Aerial Phenomena and their effects on aviation safety. By the way, Dr. Haines finds the UFO designation for the phenomena so distasteful, he refuses to appear on Podcast UFO. Most pilots prefer to remain anonymous, as publicly admitting to seeing a flying saucer is not usually an enhancement to their careers.
For full text version with links: Pilots and Planes Swallowed by the UFO