DHS Secretary Markwayne Mullin said it was due to a "telecommunications outage."
The Federal Aviation Administration ordered a rare nationwide ground stop Friday for all airports due to a communication issue affecting air traffic control.
Department of Homeland Security Secretary Markwayne Mullin told reporters it was due to a "telecommunications outage" and that there was no indication the incident was a "nefarious attack."
More than 1,000 flights have been canceled amid the issue.
The Federal Aviation Administration ordered a nationwide ground stop Friday for all airports due to a communication issue affecting air traffic control.
The agency's alert said the stop was "due to extraordinary circumstances and for reasons of safety."
In an update shortly after 6 p.m. ET, the FAA said that the ground stop remains in effect.
"As enroute facilities recover, flights will be allowed to depart through coordination with the air traffic control system command center."
-ABC News Ayesha Ali
Major airlines are offering travel advisories and waivers.
Delta has issued a waiver allowing passengers to change their flight at no extra cost for Friday and Saturday.
United has issued a travel alert, and told passengers, "You can reschedule your trip and we’ll waive change fees and fare differences."
"But, your new flight must be a United flight departing between November 12, 2026 and November 20, 2026. Tickets must be in the same cabin and between the same cities as originally booked," United added.
-ABC News Clara McMichael
AirSpace Intel, the contractor behind the SMART AI system that has been rolling out at facilities nationwide, put out a statement on X about the ground stop.
"The current ground stop is not based on or a result of the SMART system, any product of ASI or our integration with FAA and ATC," the company said.
-ABC News' Ayesha Ali and Clara McMichael
As of 6:04 p.m., 1,913 flights have been cancelled and 10,494 flights have been delayed nationwide amid the ground stop, according to FlightAware.
That number is expected to increase throughout the night as the telecommunications issue continues to persist.
