According to Ted Roe of the National Aviation Center for Anomalous Phenomena, there have been over 3,500 sightings of Unidentified Aerial Phenonmena by civilian, commercial, and military pilots spanning the entire history of powered flight. Many of these cases come from declassified US government reports and investigations, international reports from official sources and the direct testimony of military and commercial pilots, air traffic controllers, and radar operators.

The first recorded sighting by commercial airline pilot was a report made by United Airlines Captain E. J. Smith. He saw objects similar to those seen by Kenneth Arnold on the evening of July 4, 1947, just ten days after Arnold’s sighting. Smith and his first officer, Ralph Stevens, were flying a DC-3 airliner from Salt Lake City to Seattle when they saw five disk-shaped objects in the sky ahead of them while over Emmett, Idaho. They called stewardess Martine Morrow into the cockpit to confirm what they were seeing. She did and asked, “What are those?" Many more cases like this one have followed.