More than 3,500 planes were in the air on Friday afternoon when the Federal Aviation Administration stopped every departure from US airports. The nationwide FAA ground stop lasted more than four hours. Officials blamed overloaded routers in an aging air traffic control network, not a cyberattack and not the agency’s new SMART AI tool.
Transportation Secretary Sean Duffy first announced the order in a post on X. He wrote that a communication issue was affecting all Air Route Traffic Control Centers. These 22 centers handle aircraft at cruising altitude across the country.
What happened on Friday
Duffy said instability in radar and communications began at 3:36 p.m. Eastern time, ABC7 Los Angeles reported. The problem hit en route centers and terminal radar facilities, known as TRACONs. Al Jazeera reported that the FAA issued the ground stop at 3:54 p.m., citing “extraordinary circumstances and reasons for safety.”
Planes already flying could continue and land. Departures stayed on the ground until 8:15 p.m. Eastern, when Duffy said the stop was lifted, according to Fox Business.
The scale was large. Flight tracker Flightradar24 counted more than 4,700 cancellations and 10,000 delays on Friday, with about 700 more cancellations for Saturday, Al Jazeera reported. Data firm Cirium said about 11,000 flights carrying over 1.5 million passengers were still due to leave after 4 p.m. Eastern. By 7:05 p.m., at least 827 flights had diverted.
Why the system failed
At a White House briefing, Duffy described routers and switches that “got overloaded with data.” He said they then began sending inconsistent data, so the FAA shut the system down. He called it an “incredibly old air traffic control system” that still relies on analog telecom and copper lines.
Officials also admitted that new technology being added to the network overloaded older parts of it, Al Jazeera reported. That caused intermittent gaps in radio and radar coverage. Duffy said there was no total loss of communications or radar.
Was it a cyberattack?
Homeland Security Secretary Markwayne Mullin said officials had found no sign of an attack. “There is no chatter. We haven’t seen any footprints,” he said, according to the San Francisco Chronicle. He called the outage “mechanically driven,” but added that officials could not rule anything out yet.
Mullin also separated the outage from the global Microsoft service failure earlier on Friday. “These are separate issues,” he said, as quoted by the Irish Star.
Where SMART fits in
The timing raised questions because the FAA had just expanded an AI planning tool. SMART stands for Strategic Management of Airspace, Routes and Trajectories. According to the FAA’s own SMART fact sheet, it is a cloud-based platform that predicts traffic flows and flags conflicts before they occur. It works as a planning layer next to existing FAA systems. Controllers stay responsible for keeping aircraft apart.
The FAA began using SMART in a limited mode on September 21 around Washington, D.C., General Aviation News reported. The tool pulls together about 200 data streams, including weather, flight paths, traffic flow and controller staffing. The FAA says staff review all of its recommendations, and local leaders can accept or reject them.
On Tuesday, November 10, the FAA told FLYING that SMART was active in the airspace of all 22 centers. The agency said it had rerouted 180 flights so far. Each saved about 10 minutes and almost 80 gallons of fuel on average. FLYING also noted that the controllers’ union raised concerns about being left out, and lawmakers urged the FAA to pause the rollout.
Air Space Intelligence, the company that built SMART, said the nationwide rollout was unrelated to the outage, Flightradar24 reported. Duffy also said the tool “isn’t plugged in” to the system that failed, according to The Hill.
What changes for you
For travelers, the outage did not hit everyone the same way. Here is how the main groups were affected, based on airline and agency statements.
- Domestic passengers: All departures from US airports stopped. Some aircraft waited hours on arrival for a free gate.
- Alaska and Hawaii: Alaska Airlines said flights within Alaska and between Hawaii’s islands were not affected. West Coast to Hawaii flights could continue, and international flights from Honolulu were cleared.
- International travelers: United said the FAA handled international departures case by case, the Houston Chronicle reported.
- Canada: Nav Canada said its systems ran normally. It still set traffic management measures at the country’s four largest airports, and Canadian airports suspended many US flights, The Canadian Press reported.
Steps to take now
- Check your flight status in the airline app before leaving for the airport. Alaska Airlines gave this advice directly.
- Look for a travel waiver. United and Delta issued waivers, and Alaska put a flexible travel policy in place.
- Expect knock-on delays. Duffy said flights would resume slowly, depending on where pilots and flight attendants are.
The ground stop is over, but the schedule is not fixed yet. Planes and crews ended the day in the wrong cities. CNBC reported that delays and cancellations would stretch into the weekend. Duffy said he expects the system to be ready for Thanksgiving travel.
A pattern of telecom failures
Friday’s event was the second nationwide departure stop since September 11, 2001. It follows several smaller outages tied to the same aging network.
| Date | Event |
|---|---|
| January 2023 | A NOTAM system failure triggers a nationwide ground stop of about two hours. |
| August 6, 2026 | A telecom outage at Minneapolis Center halts traffic in its airspace. |
| September 2026 | A circuit failure in Philadelphia and a cut backup fiber line disrupt about 9,500 Northeast flights. |
| September 21, 2026 | SMART starts limited use around Washington, D.C. |
| November 10, 2026 | The FAA says SMART is active at all 22 en route centers. |
| November 13, 2026 | Router overload leads to a nationwide ground stop of more than four hours. |
Sources for the table: Nextgov, AeroCorner, Airways, General Aviation News and FLYING.
The $50 billion question
Duffy used the briefing to ask Congress for $50 billion to rebuild air traffic control. Congress approved $12.5 billion last year. Duffy has said the full new system will cost $31.5 billion, with a target date at the end of 2028, Nextgov reported. In September, he also floated a separate $30 billion request for towers, telecom and airports, according to Airways.
“It’s going to continue to fail,” Duffy said of the current infrastructure, as CNBC reported. Al Jazeera noted that a September government audit had already warned about copper cables from the 1960s and poorly scheduled changes that overwhelmed the system.
What remains unclear
Several key points are still open. Officials have not named the exact upgrade that overloaded the routers. They also have not said who scheduled it, or why it ran during a busy Friday afternoon. Mullin has not formally closed the cyberattack question. Finally, the FAA has not explained how it will test future network changes before they reach live traffic. Those answers will matter more than the funding request in deciding whether this happens again.
