More than 6,400 Saturday flights are gone.

WASHINGTON — By 9:35 p.m. Eastern on Saturday, airlines had canceled more than 6,400 U.S. flights and delayed more than 8,000, FlightAware told Reuters. That is one Saturday count, taken at night. It is not the “more than 3,700” cancellations and 2,000 delays this paper printed Saturday morning. The two hours are not added together.

Friday is a third count. Reuters reported about 9,200 cancellations and 7,500 delays on Friday, after the ground stop. Those are not folded into Saturday. As of the same Saturday-night dispatch, 875 Sunday flights were already canceled. That 875 is not added to the 6,400.

Bryan Bedford, the FAA administrator, said airline operations should be largely back to normal by late Sunday. Reuters reported that he apologized, and that he said the system remains stable. Officials blamed routine maintenance that went wrong: a router installation that overloaded communication centers. This desk is not adding a cause the wire did not give.

The photograph is earlier on Saturday, Nov. 14, at Ronald Reagan Washington National Airport in Arlington, Virginia. A passenger stands with his back to the camera and looks at the departures board. The screens in the frame read 7:36 a.m. and 7:37 a.m. His face is not the picture. Eric Lee, Reuters. It is not the 9:35 p.m. count, and it is not Sunday morning.