Transportation Secretary Sean Duffy said Saturday he did not believe Friday’s nationwide air travel shutdown was cyber-related, but rather due to work on updating the system’s aging telecommunications lines.
“Was this a cyberattack? Did some foreign nation attack this network? And the answer to that is we don’t believe so,” Duffy said at a news conference.
He said the problem that led the Federal Aviation Administration to make the extraordinary decision on Friday to halt all flights across the United States was pinpointed to one facility. “Once we were able to isolate the work that was being done at this remote location, all of our systems came back online,” he said.
The more than four-hour ground stop brought air travel in the United States to a complete standstill and scrambled travel plans for hundreds of thousands of passengers, persisting well into the weekend.
More than 24 hours later, President Donald Trump had not issued a statement or addressed the nation about the highly unusual event. But he posted a quote from Sen. John Kennedy, R-La., urging Congress to pass FAA funding.
The ground stop was widely criticized by Democratic lawmakers.
Rep. Hakeem Jeffries, D-N.Y., who is the leading contender to become House speaker in the next Congress, said the incident was “the latest in a series of unacceptable air travel incidents under the Trump Administration’s failed leadership.” New York Gov. Kathy Hochul put the blame squarely on Duffy and called on the transportation secretary to resign or be removed.
“There must be full public transparency on what happened to our air travel systems and why,” Rep. Robert Garcia, D-Calif., said in a post on X Saturday. “We need answers to ensure our systems and technology are funded and upgraded to ensure the safety of the public.”
Speaking to reporters on Saturday, FAA Administrator Bryan Bedford said because authorities were initially unable to assess the cause of the instability in air traffic control systems, they implemented a ground stop “to remove pressure from the system” and “ultimately to relieve stress and complexity in the airspace.”
“I think that was the right call,” he said. “We stand behind that.”
Duffy said an FAA contractor had been conducting routine maintenance to switch from old copper wire to fiber, which he described as “pretty straightforward work.” That particular network belonged to L3 Harris, Duffy said, the FAA’s legacy telecom provider.
“Either through contractor error or a faulty piece of equipment, that router that was being replaced as we switched from copper to fiber, it started flooding other routers in our air traffic control system,” Duffy said.
“What we’re working to determine was whether we had incompetence, meaning was it user error or installation error from L3Harris,” he added.
L3Harris issued a statement on Saturday, saying, in part: “We are supporting the FAA in its investigation to understand the conditions that led to the Nov. 13 ground stop of our nation’s air travel. L3Harris takes the nationwide ground stop and its impact on travelers, airlines and air traffic operations seriously.”
Once authorities were able to isolate that location and take it offline, the system was restored, Duffy said. He said authorities have not determined the root cause, but the FAA chief was more forceful in ruling out a potential cyber-related reason.
“I do think we’ve identified the fault, and I want to reiterate: We see zero evidence of anything nefarious, and zero evidence of anything AI-related,” Bedford added.
Rep. Glenn Ivey, D-Md., warned Saturday that the FAA shutdown was a wake-up call for U.S. preparedness.
“You had the Microsoft outage the other day. You had this yesterday. We need to be ready to make sure that if there are cyberattacks or anything connected with that, we’re prepared to have countermeasures to defend against it, and we’re not there yet,” Ivey said during an appearance on MS NOW’s “The Weekend.”
The FAA expected up to 5,000 flight cancellations on Saturday, Bedford said, but he anticipated air travel would resume to normal levels by Sunday.
“So I do think the worst is behind us,” he said.
But air travel remained a nightmare for many passengers. According to FlightAware, more than 5,409 flights were canceled Saturday and nearly 6,600 more were delayed.
Both Bedford and Duffy urged Congress to pass more funding to modernize the outdated systems.
“This is a bipartisan issue. Safety is paramount, but efficiency and reliability of the system is also extremely important for the American traveling public,” Bedford said.
Sheena Jones contributed to this report.
