TL;DR
The FAA ordered a nationwide ground stop on Nov. 13 after radar and communications instability affected air traffic facilities, according to Transportation Secretary Sean Duffy. The stop lasted about four hours and 23 minutes; officials said they had seen no evidence of a cyberattack, and no written root-cause report has been published.
The FAA Air Traffic Control System Command Center issued its nationwide ground-stop advisory at 3:54 p.m. Eastern time, directing departing traffic to remain on the ground. The advisory cited “extraordinary circumstances” and safety. The FAA’s cancellation notice listed an end time of 8:16 p.m.; Duffy said the airspace reopened at 8:15 p.m. The duration, calculated from the advisory event times, was about four hours and 23 minutes.
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Duffy said the FAA first experienced instability at about 3:36 p.m. in radar and communications at en route centers and terminal radar approach control facilities, known as TRACONs. He attributed inconsistent data to overloaded legacy analog telecommunications switches and routers. He said the system did not lose all radar or telecommunications capability. Earlier, FAA advisories cited equipment and communications issues affecting Chicago O’Hare and Midway; the national order followed.
Duffy said more than 3,500 aircraft were airborne when the stop began, falling to fewer than 400 by 8 p.m. Medevac, life-saving cargo and law enforcement flights were permitted to continue. FlightAware reported 9,159 cancellations within, into or out of the United States on Friday and 3,515 more by 7:58 a.m. ET Saturday. Those totals cover all cancellations during those periods and do not isolate cancellations caused by the ground stop.
How the Stop Disrupted Travel
A nationwide departure halt affects airlines, passengers and businesses that rely on air cargo, even when aircraft already in the air can continue to land. As flights are held and then released, schedules can remain disrupted after the official stop ends: aircraft and crews may be out of position, and passengers may face missed connections or cancellations. The reported cancellation figures show the scale of disruption across the two days, but they cannot be attributed solely to the FAA order.
The duration also stands out in recent U.S. aviation history. BBC News described it as the longest nationwide ground stop since the Sept. 11, 2001 attacks. The source material says the only other nationwide stop since then was in January 2023 and lasted about one hour and 40 minutes. A stop of this scale puts attention on the resilience of systems that coordinate air traffic across the country.
Duffy warned that similar disruptions could recur without investment in replacement systems, and said he wants $50 billion for modernization. That is his stated assessment and funding request; it does not establish that the same failure will happen again or specify a timetable for upgrades.
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From Chicago Delays to Nationwide Halt
FAA advisories show equipment-related problems appearing first around Chicago. At 3:21 p.m. ET, the Command Center warned of arrival delays and airborne holding at O’Hare of up to 30 minutes, citing equipment issues. At 3:28 p.m., it stopped departures to O’Hare from U.S. and some Canadian airports, listing equipment or outage and “comms issues” as the cause. Midway followed at 3:31 p.m. The Command Center also activated a diversion recovery tool for all airports that afternoon.
At 3:54 p.m., the nationwide advisory extended the ground stop to all airports. At 4:20 p.m., another advisory said airborne holding could be expected at any airport. The order was cancelled shortly after 8 p.m. The FAA advisories and Duffy’s public account provide the main available timeline; the material provided does not include a completed technical investigation.
The scope of the order and its length distinguish this event from ordinary weather or traffic delays, but the available information does not describe a total nationwide loss of radar or communications. Duffy explicitly said some capability remained. That distinction matters when describing both the operational response and what is known about the equipment problem.
““ALL AIRPORTS ARE GROUND STOPPED.””
— FAA Air Traffic Control System Command Center, advisory issued Nov. 13
The Cause Remains Under Review
Officials have not released a written root-cause report explaining which equipment failed, why it became unstable or how the issue spread from the Chicago-area advisories to a nationwide stop. Duffy blamed overloaded analog telecommunications switches and routers, but the available source material does not provide an independent technical assessment or a detailed account of the failure sequence.
Mullin said officials had found no evidence of a cyberattack and that the problem appeared mechanically driven, while also saying an attack had not been ruled out. Duffy and the maker of the FAA’s new SMART traffic tool said SMART was not connected to the failed equipment. The available information does not establish a cyber cause, nor does it make the investigation’s final conclusion clear.
The flight cancellation totals also have limits: they count cancellations across the relevant days and do not identify which were directly caused by the ground stop. The sources provided do not give a final tally of passengers affected or a full accounting of the economic cost.
FAA Review and System Funding
The next key development is a detailed FAA account of the equipment instability, its cause and any corrective measures. No publication date for a written root-cause report is given in the source material. Until the agency releases more information, it remains unclear whether the affected equipment has been repaired, replaced or otherwise protected against a similar failure.
Duffy has called for $50 billion in funding to modernize air traffic systems and warned of future disruptions without investment. Congress would need to decide whether to provide funding and on what schedule. For travelers and businesses, the immediate practical step is to check directly with airlines for current flight status and rebooking information, since the reported cancellation counts do not predict an individual flight’s status.
Key Questions
Why did the FAA halt departures nationwide?
Transportation Secretary Sean Duffy said radar and communications became unstable at FAA en route centers and terminal approach facilities. He attributed inconsistent data to overloaded legacy analog telecommunications switches and routers. A written root-cause report has not been published.
When did the ground stop begin and end?
The FAA issued its nationwide order at about 3:54 p.m. ET on Nov. 13, 2026. Its cancellation notice listed 8:16 p.m. as the end, while Duffy said the airspace reopened at 8:15 p.m. The reported duration was about four hours and 23 minutes.
Was the disruption caused by a cyberattack or the FAA’s AI tool?
Homeland Security Secretary Markwayne Mullin said officials had seen no evidence of a cyberattack, while noting it had not been ruled out. Duffy and the maker of the FAA’s SMART traffic tool said SMART was not connected to the failed equipment. The final cause has not been established in a published report.
How many flights were cancelled because of the stop?
FlightAware counted 9,159 cancellations within, into or out of the United States on Friday and 3,515 more by 7:58 a.m. ET Saturday. Those totals include all cancellations in those periods, not just ones caused by the ground stop, so the number directly attributable to the order is not specified.
Source: Thorsten Meyer AI
