Project Blue Book Case #1364. On June 29, 1951, an unidentified object was observed at O'Hare Airport in Chicago — which was under construction to become the world's busiest airport. This early O'Hare sighting predated the facility's full opening and added to Chicago's extraordinary collection of Blue Book unknowns.
O'Hare would later make UFO news again in November 2006 when United Airlines employees reported a disc-shaped object hovering over Gate C17 — a case that generated enormous media attention. The 1951 case was a precursor, establishing that unexplained phenomena had been observed at the facility from its very beginning.
The case was classified "Unknown."