CHICAGO.

on November 7, 2006, a United Airlines mechanic working at Chicago O'Hare International Airport spotted a metallic, dark grey disc hovering above Gate C-17. He alerted the United Airlines push-back tug operator, who notified the flight crew of United Flight 446 — and within minutes, at least a dozen United employees on the ramp and a number of pilots were watching the object. Witnesses estimated it to be 6 to 24 metres in diameter, completely silent, and at low altitude beneath the overcast cloud deck.

After several minutes, the object accelerated vertically through the cloud layer with sufficient force to leave a clearly defined circular hole — described by witnesses as appearing to punch through the clouds and remaining visible for several minutes after the object's departure. Photographs of the alleged hole have not been independently verified, but the visual phenomenon was reported consistently by multiple ramp employees.

The FAA initially denied any awareness of the event. After the Chicago Tribune's Jon Hilkevitch obtained a recording of a United supervisor's call to the FAA's air traffic control tower, the agency acknowledged the call but classified the incident as a "weather phenomenon" — most likely a hole-punch cloud — and declined further investigation. United Airlines initially denied that any of its employees had reported a UFO, then later acknowledged the calls.

The O'Hare case is significant for the credentialing of its witnesses (commercial pilots, certified mechanics, and ramp staff with safety responsibilities), its location at one of the busiest airports in the world, and the documented refusal of both United Airlines and the FAA to investigate further. The Tribune's reporting marked one of the first major mainstream US newspaper treatments of a UFO event in many years.