Fox News reports that FlightAware has counted 4,467 cancellations and 10,079 delays on flights within, into or out of the US during the FAA ground stop.
That puts a named data provider and an exact number in the same range as the "more than 4,000" cancellations ABC News reported earlier without a source. ABC News has not said where its figure came from.
Globally, FlightAware has recorded 5,141 cancellations and 26,196 delays, according to Fox News.
The Fox News live blog, last updated at 7.44pm ET on 13 November, does not say what time the count was taken or what period it covers. The figures have not been independently checked.
The US cancellation total is more than double the 1,913 that FlightAware showed as of 6.04pm ET, as reported by ABC7 San Francisco. The delay figure is lower than the 10,494 recorded at that time. Flightradar24 has put cancellations at more than 1,000.