At about 3:54 p.m. Eastern on Friday 13 November 2026, the Federal Aviation Administration ordered a nationwide ground stop: no departing flights from any US airport. It lasted more than four hours, the longest national ground stop in 25 years, and about 3,500 aircraft were already in the air when it began.
The cause, according to officials, was not a cyberattack. It was a piece of network equipment that started flooding the air traffic control system with traffic during a routine upgrade.
The short version
- What: a nationwide FAA ground stop for more than four hours on the afternoon and evening of Friday 13 November.
- Why: a router in El Dorado, Arkansas, began broadcasting data into the network while a contractor was replacing copper wire with fiber. Officials described about 1,000 logon attempts every four to five seconds.
- Not a cyberattack: the FAA administrator said there was "zero evidence of anything nefarious". Homeland Security said the same.
- Cancellations (FlightAware): more than 9,000 on Friday, more than 6,400 on Saturday and about 900 more on Sunday.
- Recovery: the FAA expected airlines to be back on full schedules by the end of Sunday 15 November.
- Your rights: if your flight was cancelled and you chose not to travel, you are owed a cash refund, not just a voucher.
What caused the FAA ground stop?
Transportation Secretary Sean Duffy gave the most detailed account. During work to replace copper wiring with fiber, a router in El Dorado, Arkansas, began broadcasting data into the network. A system in Amarillo, Texas, that had been replaced about three weeks earlier was also flooded. The traffic overloaded the telecommunications links that air traffic control facilities depend on.
The router's technology and IT support come from L3Harris, a government contractor, and the unit is now in the company's Florida lab. Duffy said broadcasting on all 69 routers of that type in the national airspace system has been switched off, which resolved the problem.
FAA Administrator Bryan Bedford said the agency issued a nationwide stop "out of an abundance of caution" because, at first, it could not explain why so many facilities were affected at once.
The union representing FAA technicians, PASS, said its members were not involved in the upgrade work that triggered the outage.
How bad was the disruption?
| Day | Flights cancelled (FlightAware) |
|---|---|
| Friday 13 November | more than 9,000 |
| Saturday 14 November | more than 6,400 |
| Sunday 15 November | about 900 and rising at the time of reporting |
Cancellations ran on into the weekend because aircraft and crews ended Friday night in the wrong cities, and crew duty-time limits stop airlines simply flying everyone through the night.
Was it a cyberattack?
Every official account says no. Duffy said he did not believe it was a cyberattack, but rather an FAA system that did not "meet the moment". Homeland Security Secretary Markwayne Mullin said there were no indications of an attack, and Bedford said there was no evidence of anything AI-related either.
What happens next?
Duffy asked Congress for $50 billion to modernise air traffic control systems, and President Trump urged lawmakers to approve it, blaming the previous administration. Lawmakers from both parties are demanding answers. With a funding deadline on 11 December and a new Democratic Congress arriving in January, the money is likely to become part of the wider budget fight.
Am I owed a refund for a cancelled flight?
Under US Department of Transportation rules, if an airline cancels or significantly changes your flight and you decide not to travel, you are entitled to a full cash refund, including for non-refundable tickets. You do not have to accept a voucher or travel credit. The refund rule applies whatever the cause of the cancellation, including air traffic control outages.
What you are generally not owed is compensation for missed hotels, connections or events when the cause is outside the airline's control. Check your credit card's travel protection, which often covers delay expenses.
Airlines also loosened rules. American Airlines waived change fees for travel through Wednesday 18 November, and Delta urged flexible travellers to move to Monday or later.
Does this affect Thanksgiving travel?
The FAA expected full recovery by Sunday night, well ahead of the holiday rush from Tuesday 24 November. But the outage has made airlines and travellers nervous at the worst possible moment, with average Thanksgiving fares already up 17%. Our Thanksgiving 2026 travel guide has the numbers.
The lesson for any business
One router, during a routine upgrade, stopped a whole country's aviation for an afternoon. It is the single-point-of-failure problem every operations team has in miniature: a shared network, a change made by a contractor, and no quick way to tell which facility is the source. Three habits would have helped here, and help in any business:
- Change windows with a rollback. Infrastructure work is scheduled away from peak load, with a tested way to undo it.
- Segmentation. One misbehaving device should not be able to flood every site.
- A rehearsed "stop everything" decision. The FAA's choice to halt everything while it diagnosed the problem was the right one. The cost is in how long the diagnosis takes.
Frequently asked questions
Why were all US flights grounded on 13 November 2026?
A router failure during a copper-to-fiber upgrade flooded the telecoms network used by air traffic control, and the FAA halted all departures nationwide while it found the source.
How long did the FAA ground stop last?
More than four hours, from about 3:54 p.m. Eastern on Friday 13 November. It was the longest nationwide ground stop in 25 years.
How many flights were cancelled?
More than 9,000 on Friday and more than 6,400 on Saturday, according to FlightAware, with hundreds more on Sunday.
Was the FAA outage a cyberattack?
Officials at the FAA, the Department of Transportation and Homeland Security said there was no evidence of a cyberattack.
Sources
ABC News live updates; ABC News on the lifted ground stop; CBS News; CNN; Al Jazeera; US DOT refund rights. As of 15 November 2026.
