FAA Ground Stop Traced to Aging Routers After 9,159 Cancellations

A rare nationwide FAA ground stop halted departures from every US airport for about five hours on Friday, Nov. 13, 2026, and led to 9,159 canceled flights that day. Officials now blame overloaded, decades-old network routers, not a cyberattack, and the disruption is still rippling through Saturday schedules.

A ground stop is an order that keeps departing aircraft on the ground while planes already in the air continue to their destinations. The FAA cited "extraordinary circumstances and for reasons of safety," CBS News reported.

Transportation Secretary Sean Duffy announced the stop on X, citing a communication issue affecting all Air Route Traffic Control Centers, the regional centers that manage aircraft crossing the country. AirSafe.com's Todd Curtis told Al Jazeera there are 21 such centers.

What caused the nationwide outage?

So far, officials have pointed to overloaded routers and unstable data flow inside the FAA Telecommunications Infrastructure, or FTI, the network that links air traffic control centers. Duffy said the routers became overloaded with data and began providing inconsistent information. "Because of that, we shut the system down," he said, adding that it was not a total loss of communications or radar.

CBS News, citing senior government sources, reported that the FAA's preliminary investigation points to Cisco 600 series routers made between 2001 and 2006. CBS also said the faulty equipment was identified and isolated. Those sources said the overloaded routers sent out-of-sync data packets into the air traffic control system, causing static on voice lines and screens that flashed or went black.

Other sources told CBS News something different: that a private communications network update may have triggered a reboot and crash. Homeland Security Secretary Markwayne Mullin said new security patches introduced into the older system appeared to "overwhelm" its routers. For broader context on Cisco, see our recent coverage of Cisco's latest results.

Why was this outage so unusual?

Ars Technica reported that this was only the third nationwide ground stop in FAA history, after Sept. 11, 2001, and a brief stop on Jan. 11, 2023, when the NOTAM (Notice to Air Missions) system failed. Al Jazeera said it was the longest ground stop in 25 years.

FTI is run by L3Harris, whose predecessor Harris Corp. won the contract in July 2002. A November 2023 FAA-commissioned review had already called FTI obsolete and dependent on older TDM, or time-division multiplexing, technology, an older way of carrying voice and data over fixed time slots. That review warned that an unexpected failure could disconnect facilities or even a whole regional center. A GAO report in September 2026 also warned about aging infrastructure and poorly timed modernization switchovers.

How many flights were affected?

Flightradar24 told CBS News that about 3,100 airborne aircraft were bound for US airports when the stop began, and all landed safely. FlightAware, also via CBS, said Friday ended with 9,159 cancellations and 7,190 delays in the US.

Cirium said that by 7:05 p.m. ET, at least 827 flights had been diverted and 670 had returned to their departure airports. Air Canada also canceled all flights to and from the US for the rest of Friday evening, according to Ars Technica.

By Saturday morning, Nov. 14, CBS News said airspace was operating normally again at 7:30 a.m. ET. FlightAware later reported more than 3,800 cancellations and more than 2,000 delays in the US that day, with Delta (640), United (530) and American (488) canceling the most.

Was the FAA ground stop a cyberattack?

Officials say there is no indication of a cyberattack. Mullin said there was no sign of a nefarious act, and he also said there was "no connection between this and Microsoft," referring to the separate Microsoft 365 outage earlier this week.

Duffy said the airspace reopened at 8:15 p.m. ET on Friday. The FAA said it tested its systems first to confirm they were stable.

The safety of the flying public is always the FAA's highest priority. The FAA lifted the ground stop and some flight departures are resuming. Before clearing flights to resume, we thoroughly tested our systems to confirm they were stable and that operations remain reliable.

— The FAA (@FAANews) November 14, 2026

On Saturday, he said operations were slowly returning to normal, but warned that delays and cancellations would continue as airlines reposition crews and aircraft.

What happens next?

Duffy renewed his call for emergency funding from Congress. "You will have more of them unless the American people and the Congress tell us to build," he said. Mullin said the administration wants a full replacement of the air traffic control system, at an estimated $50 billion.

That matters for travelers heading into the Thanksgiving peak, which begins in under two weeks. If you are flying this weekend, check your airline app directly and expect rebooking delays, since crews and planes may be out of position.

Our take: This outage shows how one weak layer of old network gear can disrupt departures nationwide. Aviation is built on redundancy, yet backups did not keep departures moving. The 2023 review already warned about FTI's aging design, so the real fix is not just new hardware. It is funding, careful modernization timing, and real redundancy across the system. Until the full investigation ends, the Cisco router detail remains a preliminary finding from sources.