Officials say router maintenance may have caused the longest nationwide halt since 9/11. Thousands of flights were canceled.
The FAA ground stop that halted air traffic across the United States on Friday may have been triggered by routine maintenance on a communications router, US Transportation Secretary Sean Duffy said Saturday, as airlines worked to reset schedules after thousands of cancellations.
Duffy told reporters in Washington that a router was being upgraded from copper to fiber at what he described as a very remote location on Friday. He said contractor error or faulty equipment caused it to start flooding other routers in the air traffic control system, producing roughly 1,000 connection attempts every four to five seconds, according to Al Jazeera.
What caused the FAA ground stop
Duffy said the disruption affected radar feeds and communications between controllers and aircraft, prompting the order to shut the airspace, a decision he said was driven by safety. The Federal Aviation Administration lifted the restrictions after more than four hours, Fox News reported.
The Transportation Department identified the contractor for the maintenance as L3Harris, which has been tasked with modernizing the FAA’s communications system. Duffy said investigators have not determined whether the fault was an installation error or a faulty router, and that his agency would hold people accountable.
L3Harris told Al Jazeera it is working closely with the FAA and treats the shutdown and its effect on travelers seriously. The company said it is supporting the investigation into the conditions behind the Nov. 13 ground stop.
Officials rule out cyberattack
Duffy said the government does not believe a cyberattack caused the outage, noting that systems came back online once work at the location was isolated. FAA Administrator Bryan Bedford said officials saw zero evidence of anything nefarious or anything related to artificial intelligence. Bedford said a root cause analysis would be released publicly when it is complete.
Al Jazeera described it as the longest nationwide ground stop since the Sept. 11, 2001, attacks and only the second since then.
Cancellations continue
Fox News reported that more than 10,000 flights were canceled across Friday and Saturday, affecting more than 1.5 million scheduled passengers after 4 p.m. Eastern on Friday alone. FlightAware data cited by Fox showed nearly 4,000 US flights canceled on Saturday, and more than 15,000 flights had been affected overall.
Bedford said crews and aircraft were out of position for about 12,000 flights that were lost. He said the FAA expects 4,000 to 5,000 of the 41,000 flights scheduled for Saturday to be canceled, which he said should set up a full recovery on Sunday. He said he believes the worst is behind the system. The FAA said it expects full schedule integrity by the end of Sunday.
Airlines offer waivers
Fox News reported that the five largest US carriers issued travel waivers for Friday and Saturday flights. American Airlines is allowing free rebooking in the same cabin for travel through Nov. 17, if the change is made by Saturday, and said it would prioritize flights to non-hub cities and international flying. Delta Air Lines is allowing travelers to rebook for departure on or before Nov. 21 without extra fees or fare differences. United Airlines set a rebooking window through Nov. 20, and JetBlue through Nov. 18.
Southwest Airlines is offering flexible options for reservations from Nov. 13 through Nov. 16. Passengers whose flights are canceled are entitled to a full refund under Transportation Department rules if they decline a voucher or other compensation, Fox reported.
Calls for funding
Homeland Security Secretary Markwayne Mullin attributed the incident to the FAA’s aging infrastructure, Fox News reported, and Duffy called on Congress to provide $50 billion in emergency funding for modernization. Duffy said the FAA depends on L3Harris as its prime contractor and cannot easily turn elsewhere.
The ground stop came during a week of technology failures, with Fox reporting a Microsoft email outage that was resolved early Saturday and a Workday outage on Friday. Officials have not linked those incidents to the FAA disruption.
What happens next
The FAA’s root cause analysis has no announced release date, and Duffy said his department is still working to determine what failed and who is responsible.
Sources: Al Jazeera and Fox News reports of Nov. 14, 2026