No flights have left Chicago O'Hare in more than two hours, according to Flightradar24 data reported by CNN.
CNN reports that the last recorded take-offs at JFK and Reagan National were at 3.35pm ET. Several other major airports had seen no departures since before 4pm ET, according to a Flightradar24 post at 5.25pm ET cited by CNN.
This adds a take-off record to the earlier count from the flight tracking app Flighty, reported by TheStreet, of at least 114 aircraft on the ground at O'Hare.
The figures come from a flight tracking service and not from the FAA. They have not been independently checked.