The Federal Aviation Administration ordered a nationwide halt to departing flights on Friday 13 November after communications failures disrupted US air traffic control centres, in one of the rarest shutdowns of American air travel.
The FAA announced the ground stop at approximately 3.54pm Eastern Time (8.54pm GMT) on Friday, citing extraordinary circumstances and safety concerns. The immediate problem involved communications systems used by air traffic control facilities. The cause had not been officially established at the time of this report.
Update, 14 November 2026: The nationwide ground stop was lifted at 8.15pm Eastern Time on Friday. Officials have blamed overloaded, ageing air traffic control network equipment, although the full investigation continues. Read our latest FAA ground stop update.
What we know
- The order stopped flights from taking off at US airports. It was not an instruction for aircraft already airborne to land immediately.
- Aircraft already in the air continued to be handled by controllers and were permitted to land. International flights entering the United States were managed individually.
- Transport Secretary Sean Duffy said communications issues were affecting the country’s 22 regional en-route air traffic control centres, which manage aircraft flying between airport areas.
- The FAA said the measure was precautionary while technicians investigated and worked to restore reliable communications.
- The communications failure caused major delays and cancellations, including disruption to transatlantic travel.
By approximately 6.40pm Eastern Time (11.40pm GMT), FlightAware had logged more than 3,220 cancellations and about 10,200 delays involving flights to, from or within the United States, according to Business Insider. Those figures were a snapshot of all US-related disruption at the time of reporting; they should not automatically be interpreted as flights affected solely by the communications failure. Airlines warned that repositioning aircraft and crews could prolong disruption into the weekend.
Why would a communications failure stop flights nationwide?
Air traffic controllers rely on reliable voice and data communications to coordinate departures, maintain safe aircraft separation and transfer responsibility as planes cross airspace boundaries. Pilots also have procedures for communications failures, but those procedures are not a substitute for a fully functioning national control network.
A ground stop reduces the number of additional aircraft entering an already strained system while controllers manage planes that are flying. The nationwide scope was especially unusual: the previous such halt was in January 2023, when an FAA pilot-notification system failed. Before that, the comparison was the shutdown following the 11 September 2001 attacks.
Video: explaining the FAA ground stop
The following TMZ video discusses the nationwide grounding. It is included as explanatory commentary, not as an official finding about what caused the outage.
What officials have said
Homeland Security Secretary Markwayne Mullin said officials had no indication at that stage of a malicious or terrorist attack. He emphasised that aircraft in the air had been accounted for and said the immediate priority was keeping passengers safe while the technical investigation continued.
That reassurance is not the same as a completed investigation. Officials had not published a definitive root cause, and the absence of early evidence of a cyberattack does not, on its own, establish exactly what went wrong.
Was the FAA failure connected to Microsoft’s global outage?
The timing is striking. Microsoft 365 services, including Outlook, Teams and Copilot, experienced major disruption beginning on Thursday 12 November and extending into Friday. Fish 4 News reported separately on the Microsoft outage.
However, there is no verified evidence that the Microsoft failure caused the FAA ground stop. Microsoft said it had no indication its services were involved, and Mullin said investigators were not drawing a connection. Microsoft described problems affecting its own service infrastructure, while the FAA described failures in aviation communications. Investigators must establish any shared dependency before a connection can be responsibly reported.
Did the new FAA AI system cause the problem?
Three days earlier, on 10 November, the FAA announced nationwide expansion of its AI-supported Strategic Management of Airspace, Routes and Trajectories system, known as SMART, across the airspace served by all 22 regional centres.
According to the FAA’s published explanation, SMART combines approximately 200 data streams to advise specialists on routing and scheduling. FAA personnel review recommendations before they reach operational facilities; the technology is not intended to replace controllers or directly fly aircraft.
The developer, Air Space Intelligence, said the ground stop was not caused by SMART, any of its products or its FAA integration. Officials had not published evidence contradicting that statement. The proximity of the rollout and the communications failure is therefore a legitimate question for investigators, not proof of causation.
And what about the nationwide emergency alert test on 17 November?
The Federal Emergency Management Agency and Federal Communications Commission have scheduled a nationwide Emergency Alert System test for Tuesday 17 November 2026 at 2.20pm Eastern Time. It is a planned test of how broadcast and other participating communications providers relay emergency warnings.
Crucially, the test was announced weeks before the aviation outage. It is not evidence of an emergency declaration, a coordinated shutdown or a connection to either the FAA or Microsoft incident. The scheduled activity concerns public warning broadcasts, rather than air traffic control operations.
What we don’t yet know
- The underlying technical fault and whether a specific network component, software change or telecommunications provider was responsible.
- Why the failure affected communications across so many air traffic control facilities and how backup arrangements performed.
- Whether a formal technical investigation will identify any common dependency with separate technology outages.
- The precise point when the nationwide restriction will be fully lifted and how long airline schedules will take to recover.
Passengers should check flight status directly with their airline rather than rely on general airport disruption totals. The FAA’s air traffic status service publishes operational advisories, although airline schedules may remain disrupted after restrictions are lifted.
Sources
- Reuters: nationwide FAA ground stop, flight disruption and official comments
- Associated Press: developing FAA investigation and statements
- Federal Aviation Administration: 10 November SMART statement
- FAA: SMART system launch and operation
- FEMA: advance notice of 17 November emergency alert test
- The Guardian: Microsoft 365 outage and recovery updates
