This local source record summarizes "Report of an unidentified aerial phenomenon and its safety implications at O'Hare International Airport", published or preserved by NARCAP report / The Black Vault mirror.
The independent aviation-safety report analyzes witness accounts, FAA audio and operational implications of the 7 November 2006 O'Hare report.
NARCAP is an independent research group, not the FAA; its analysis is not an official finding, and no verified image of the reported object is available.