All departing US flights grounded for hours after air traffic control communication outage: what went wrong

Updated 15 November 2026

Departing flights across the United States were grounded for several hours on Friday, 13 November, after a communication failure hit the country’s air traffic control network. The Federal Aviation Administration (FAA) ordered a nationwide ground stop citing “extraordinary circumstances” and safety. Flights were cleared to resume at about 8:15 pm Eastern time, but thousands of cancellations spilled into the weekend.

What happened

Late on Friday afternoon, the FAA reported communication problems affecting its Air Route Traffic Control Centers, the facilities that guide planes between airports. With controllers unable to rely on their systems, the agency stopped departing flights nationwide. About 3,100 planes bound for US airports were already in the air when the stop began, according to Flightradar24 data, and officials said they landed safely. Some international flights and services within Alaska and Hawaii continued.

Reports differ on how long the stop lasted, putting it at between about four and five hours. Airlines were cleared to restart at around 8:15 pm Eastern time on Friday, which was early Saturday morning in India.

What caused the outage?

Officials have said this was a technical failure, and the investigation is still preliminary.

• Transportation Secretary Mr. Sean Duffy said routers in the system “became overloaded with data” and began giving inconsistent information, so the system was shut down. He called the air traffic control system “incredibly old”.
• Homeland Security Secretary Mr. Markwayne Mullin said it was “just a telecommunication outage” and that there was “no indication” of a deliberate attack. He also said new security patches added to the older system appeared to overwhelm its routers.
• Senior government sources have been reported as saying that the preliminary investigation points to routers made between 2001 and 2006, which have been identified and isolated. The network involved is the FAA Telecommunications Infrastructure, run by the contractor L3Harris, which has not commented publicly.
• Other reports said the trouble came during an equipment upgrade, from copper wiring to fibre, at one FAA facility.

Mr. Mullin also said there was no connection with the Microsoft outage that hit Outlook and Teams in the same week.

How many flights were affected

Friday was reported to be the second-worst day of the year for US airlines, after a snowstorm in January. On Saturday, Delta, United and American had the most cancellations, and Atlanta, Chicago O’Hare and New York’s JFK were among the worst-hit airports. Most big US airlines issued travel waivers so passengers could rebook without a fee.

What happens next

FAA Administrator Mr. Bryan Bedford said on Saturday that the system “remains stable”, and airlines expect to be back on full schedules by the end of Sunday. Mr. Duffy has asked Congress for emergency funding to modernise air traffic control and warned there would be “more of these” without it. Mr. Mullin said the administration wants to replace the whole system, at an estimated cost of about $50 billion.

What it means for Indian travellers

If you are flying to, from or within the US in the next few days, check your flight status directly with the airline before leaving for the airport, and keep an eye on connecting flights, which are the ones most likely to be missed. Under US Department of Transportation rules, you can get a refund if a flight is cancelled or significantly changed and you choose not to travel. Hotel and meal costs are usually not covered for outages like this, so check your travel insurance.

Frequently asked questions

Was the US flight outage a cyberattack?

Officials have said there is no indication of a cyberattack. They blame a telecom failure linked to old routers, though the investigation is still going on.

Are US flights back to normal?

Flights resumed on Friday night, but cancellations continued over the weekend. Airlines expect normal schedules by Sunday evening.

Can I get a refund?

Yes, if your flight was cancelled or significantly delayed and you choose not to travel, under US rules.

Questions to think about

• Should critical systems like air traffic control be allowed to run on equipment that is decades old?
• How much should governments spend to modernise infrastructure before it fails?
• Is India’s own air traffic network ready for a failure like this?