US air traffic is on track to return to normal by Sunday evening following a nationwide ground stop caused by a failed software upgrade.
The Federal Aviation Administration ordered a complete shutdown of departures across 22 air traffic control centres at 15:36 Eastern time on Friday, November 13, 2026. The stoppage lasted over four hours and halted roughly 3,500 airborne planes.
Following the installation of a new router by contractor L3Harris on its Arkansas site, the device began flooding the network with data. This overloaded switches and routers, causing communications and radars to function intermittently.
The regulator’s chief, Bryan Bedford, said this instability began to propagate, prompting the decision to halt takeoffs. Department officials confirmed that no cyberattacks were involved.
The current ground stop is not based on or a result of the SMART system, any product of ASI or our integration with FAA and ATC.
“Our switches and routers were flooded with data, which led to inconsistencies in the data coming from those routers; that is why we took the system out of service,” Transportation Secretary Sean Duffy said, according to L’Express.
The FAA reported that more than 18,400 flights were cancelled across Friday and Saturday. Friday alone saw 12,000 cancellations.
The @FAAnews issued a nationwide ground stop for all U. S. airports following a communication issue impacting all Air Route Traffic Control Centers. FAA technicians are investigating the issue. We will provide immediate updates as we have them.
Nearly 6,400 additional flights were cancelled on Saturday. Over a thousand early Sunday cancellations followed as the disorganization of crews and aircraft blocked normal operations.
Louise Maher, a 47-year-old traveler blocked at Newark Liberty International Airport, told reporters she might eventually cry over her disrupted British Airways flight to London. Because the FAA was responsible rather than airlines, carriers were not legally required to compensate stranded passengers.
Canadian airports also reported widespread impacts. Airport spokesman Maxime Landry said that flights such as Montreal to Cancun were directly affected.
Air Canada reported cancelling about 250 flights on Friday alone, affecting some 27,000 passengers.
C’est franchement le bazar, Lisa Beraid told the Agence France-Presse at LaGuardia Airport in New York, as reported by Lemonde, after facing delays.
The failure drew sharp focus to the aging state of American aviation infrastructure. Decades of reliance on analog copper cables and outdated technology left the system vulnerable.
Avec un tout nouveau système ultramoderne, vous n’aurez pas ces pannes, Duffy said during his press conference, urging lawmakers to increase funding, Lemonde reported. He vowed to hold responsible parties accountable.
The ground stop stands as the most expansive nationwide aviation shutdown in the United States since the terrorist attacks of September 11, 2001. It eclipsed a brief 2023 computer failure of the NOTAM safety system that lasted under two hours and grounded roughly 9,500 flights.
Authorities expect operations to normalize gradually by Sunday evening. Recovery across airline networks is projected to take several days.
