The Federal Aviation Administration lifted its nationwide halt of all departures at 8:15 p.m. ET Friday after more than four hours. Transportation Secretary Sean Duffy blamed routers “overloaded with data,” while a separate account pointed to a software update. The cause has not been confirmed, and cancellations ran into Saturday.

Friday's order was the second nationwide ground stop of all departures since the Sept. 11, 2001, attacks. The previous halt, on Jan. 11, 2023, followed an outage in the NOTAM system used to alert pilots to hazards.

What Changed

AI-generated summary, reviewed by an editor. More on our AI guidelines.

Router overload and a reported update

Duffy said routers became “overloaded with data”, producing “inconsistency” in the information they supplied. Some routers had been replaced during his tenure, he said, but old hardware failed. He said the incident did not involve a total loss of communications or radar capabilities.

Multiple sources told CBS News that an update to the private network connecting the air traffic control system caused it to reboot and crash. The FAA Telecommunications Infrastructure network is operated by L3Harris.

Two airline officials and a U.S. official also tied the outage to the L3Harris-run network, which handles radio frequencies controllers use to communicate with pilots.

No official has confirmed what triggered the router overload or whether a software update was involved, and L3Harris had not responded to requests for comment.

Cyberattack and AI inquiries

“We have seen zero evidence that this was a cyberattack,” Homeland Security Secretary Markwayne Mullin said Friday night. “It appears this was mechanically driven.”

President Donald Trump also said the halt did not appear linked to a cyberattack or AI. Asked about a possible connection to the FAA's new AI routing tool, SMART, Mullin said, “We're looking at that.”

Air Space Intelligence denied a connection. “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 Friday. The company holds the FAA's $875 million, 12-year SMART contract. SMART is a cloud-based tool that suggests routes to manage airspace congestion.

Emergency funding and congressional review

Duffy called for $50 billion from Congress on Friday to address the aging air traffic control system.

“This is an emergency. I want Congress to give us emergency funding,” he said.

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Sen. Maria Cantwell, a Democrat, said the Commerce Committee would review the outage, including technology used for primary and backup communications frequencies. Sen. Andy Kim called the ground stop “outrageous.”

Cancellations into Saturday

FlightAware counted 9,814 delays and 5,117 cancellations within, into or out of the United States as of 8 p.m. ET Friday. Those figures cover the entire day, including disruptions before the ground stop began shortly before 4 p.m. ET.

By Friday evening, FlightAware also listed more than 700 cancellations for Saturday.

Barbara Steinberg, an accountant from Cedar Knolls, N.J., had her Porter flight to Toronto canceled and was rebooked for Saturday morning. She doubted that flight would depart.

“I get frustrated with the focus on AI when something like this impacts so many people,” Steinberg said. “They should be focused on current telecommunications and communication systems, especially for flights.”

Frequently Asked Questions

When did the FAA lift the nationwide ground stop?

The FAA lifted the halt at 8:15 p.m. ET on Friday, Nov. 13, 2026, after more than four hours. The stop began shortly before 4 p.m. ET.

What caused the outage?

Transportation Secretary Sean Duffy blamed routers "overloaded with data." Multiple sources told CBS News that an update to the L3Harris-operated FAA Telecommunications Infrastructure network caused it to reboot and crash. No official has confirmed the trigger, and L3Harris had not responded to requests for comment.

Was it a cyberattack or linked to AI?

Homeland Security Secretary Markwayne Mullin said officials had seen zero evidence of a cyberattack. Air Space Intelligence, which holds the FAA's $875 million SMART contract, said the ground stop was not a result of its system. Mullin said officials were still looking at SMART.

How many flights were affected?

FlightAware counted 9,814 delays and 5,117 cancellations within, into or out of the United States as of 8 p.m. ET Friday, figures that cover the whole day. More than 700 Saturday flights were also canceled by Friday evening.

Has this happened before?

It was the second nationwide ground stop of all departures since the Sept. 11, 2001, attacks. The previous one, on Jan. 11, 2023, followed an outage in the NOTAM system that alerts pilots to hazards.

AI-generated summary, reviewed by an editor. More on our AI guidelines.

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Editor-in-Chief and founder of Implicator.ai. Former ARD correspondent and senior broadcast journalist with 10+ years covering tech. Writes daily briefings on policy and market developments. Based in San Francisco. E-mail: editor@implicator.ai