On November 7, 2006, at least twelve United Airlines employees, including pilots, mechanics, and supervisors, observed a silent, dark metallic disc hovering above Gate C-17 at O'Hare International Airport for approximately five minutes before it shot upward through solid cloud cover, leaving a circular hole that closed behind it.

Both United Airlines and the FAA initially denied any knowledge of the incident until the Chicago Tribune filed a FOIA request, which produced a recorded phone call from a United supervisor to an FAA tower manager reporting the object in real time. The FAA attributed the sighting to a 'weather phenomenon' without further investigation.