The Federal Aviation Administration ordered a nationwide ground stop of all departing flights at all US airports on Friday, 13 November 2026, after a communications failure hit air traffic control centres across the country. The order came from the Air Traffic Control System Command Center at about 3:54 p.m. ET, as Advisory 111, titled “National Ground Stop”, and it is only the second nationwide stop of all departures since the September 11, 2001 attacks, Reuters reported.
The advisory read, in part: “DUE TO EXTRAORDINARY CIRCUMSTANCES AND FOR REASONS OF SAFETY. ATTENTION ALL AIRCRAFT OPERATORS, BY ORDER OF THE FEDERAL AVIATION COMMAND CENTER ALL AIRPORTS ARE GROUND STOPPED. ALL DEPARTING TRAFFIC SHOULD REMAIN GROUND STOPPED UNTIL FURTHER NOTICE.”
Flights already in the air were allowed to continue and land; the stop applies to departures only. Inbound international flights are managed on a case-by-case basis, CNN reported. Shortly before the nationwide announcement, the FAA halted traffic in Chicago over air traffic control communications issues, according to Reuters.
How bad is the disruption so far?
By 6:16 p.m. ET, FlightAware counted 10,494 US flights delayed and 3,396 cancelled, The Verge reported, citing FlightAware, and by 8 p.m. EST the counts stood at more than 10,000 delayed and 5,000 cancelled, NPR reported. More than 6,000 flights were cancelled by 8:47 p.m. ET, FlightAware said via WebProNews. Cirium counted 827 diverted flights, the AP reported: 670 back to origin and 157 redirected elsewhere as of 7:05 p.m. EST. About 11,000 flights carrying more than 1.5 million passengers had been scheduled to depart after 4 p.m. EST, Cirium said.
The 6:16 p.m. count, 10,494 delays plus 3,396 cancellations, is 13,890 flights affected within about two and a half hours of the 3:54 p.m. ET order. Against the roughly 45,000 flights the FAA handles on an average day, The Times reported, that is about 31% of a full day’s US air traffic. (Calculation by TechReview, from FlightAware figures reported by The Verge and The Times’ daily-flight figure.)
Flightradar24 said about 3,100 aircraft were airborne and bound for US airports by 4:20 p.m. ET, down from 4,042 when the stop began, The Black Box reported, citing Flightradar24.
What caused it, and what officials have said
US Transportation Secretary Sean Duffy posted on X at 4:16 p.m. ET that the FAA had issued the stop after a communication issue at all Air Route Traffic Control Centres. Duffy later said the disruption began at 3:36 p.m. ET, when radar and communication systems at control centres and TRACON facilities became unstable, the Economic Times reported. Duffy’s account is that a legacy communications system became overloaded and began issuing faulty data, CNA reported. That is Duffy’s account, not a confirmed FAA root cause.
At a Saturday press conference, Duffy gave the fullest account yet of what went wrong. He said the failure began during routine L3Harris maintenance, switching telecom lines from copper to fibre at a remote FAA facility, the BBC reported. The router began flooding the network with more than 1,000 connection attempts every 4 to 5 seconds, producing inconsistent data and forcing the closure for safety. Duffy said investigators had not yet determined whether the problem was contractor “incompetence” or faulty equipment. Duffy also asked Congress for $50 billion for a complete overhaul of the air traffic control system. FAA Administrator Bryan Bedford projected 4,000 to 5,000 Saturday cancellations, with a normal schedule by the end of Sunday.
Homeland Security Secretary Markwayne Mullin said after the lift, “There is no cyberattack,” and that investigators had found no evidence of a cyberattack, the Economic Times reported. Mullin also said there was no connection to Microsoft, and that the public was never in danger. Microsoft said it had “no indication that the FAA’s nationwide ground stop is related to any Microsoft services.” The FBI is examining whether a software update played a role, Bloomberg reported, citing an official familiar with the matter. The FBI does not believe a cyberattack or criminal activity caused the failure, and the cause has not been determined. The FAA told Fox News that claims of a software outage are false; a software update is not a software outage. Bedford said at the Saturday press conference, “We see no evidence of anything sinister and no evidence of anything related to artificial intelligence,” the BBC reported, and promised a root-cause analysis once complete.
Two FAA sources had told the Washington Examiner the halt was due to a “rolling frequency outage”, PEOPLE reported. That anonymous-source claim was never confirmed by the FAA or the Department of Transportation, and Duffy’s account has now superseded it.
The National Weather Service reported nationwide internet and communications issues the same day, saying some products might be unavailable or out of date. There is no confirmed connection between the Weather Service issues and the FAA ground stop, NorthJersey and News9 reported. The Weather Service said there was no radar outage and radar.weather.gov was fully operational.
Is the ground stop lifted?
Yes. The FAA lifted the nationwide ground stop at 8:19 p.m. ET on Friday, 13 November, about four hours after the 3:54 p.m. ET order, the command centre advisory said. Departures resumed, but delays and cancellations continued into the weekend as airlines worked through the backlog.
The stop was lifted at 8:19 p.m. ET, per the command centre advisory; NorthJersey reported “around 8:15 p.m.” and the Palm Beach Post “just before 8:30 p.m.” The FAA’s status page had listed the stop on and off through the evening, but no advisory cancelling Advisory 111 was issued until the lift announcement.
What should travellers do now?
The stop is over, but the disruption is not. Check your flight before leaving for the airport, and expect delays and cancellations through the weekend as airlines work through the backlog.
- Check your flight status on your airline’s app or website before heading to the airport.
- Rebook through your airline’s app or website instead of joining the long airport queue.
The last time this happened
This is only the second nationwide ground stop of all departures since the September 11, 2001 attacks. The previous one was 11 January 2023, when the FAA’s Notice to Air Missions (NOTAM) system failed after contractors accidentally deleted files, Reuters and USA Today reported. Today’s problem was different: communications issues, not a NOTAM failure.
What to watch next
What remains open: the FAA’s root-cause analysis, promised once complete; whether the weekend schedule recovers as Bedford projected; and whether investigators settle the question of contractor error versus faulty equipment.
This is not the Microsoft 365 outage of 12-13 November, and it is not the January 2023 NOTAM failure. No source connects the FAA stop to the Microsoft outage.
