What happened
Workers reported a saucer-shaped gray disc hovering below the clouds at about 1,400 ft. A United supervisor called the tower asking if anyone had seen a spinning disc-shaped object. Controllers saw nothing and radar showed nothing. The FAA first denied any report, then confirmed the call after a Chicago Tribune FOIA request by Jon Hilkevitch. The FAA said it was probably a weather phenomenon, and astronomer Mark Hammergren noted conditions were right for a hole-punch cloud.