The U.S. Federal Aviation Administration continues to investigate the highly unusual ground stoppage of all departing flights in the mainland United States yesterday. That stoppage included St. Louis and Kansas City airports, “due to extraordinary circumstance and reasons for safety” after the agency earlier reported serious air traffic control communications issues, which were thought to have been originated in the Midwest.
The flights were stopped from taking off about 3:15 Friday, with normal traffic returning about four hours later.