11,000 US flights grounded, 1.5mn passengers stranded: What led to the massive chaos?

Officials cited “extraordinary circumstances” caused by communications problems at regional air traffic control centers, according to an FAA notice.

November 14, 2026 / 08:12 IST

Travelers wait at a United airlines terminals as flights were delayed at Los Angeles International Airport on Friday. (AP photo)

Thousands of flights were cancelled and delayed in the United States, leaving over 1.5 million passengers stranded, after a telecommunications outage affected air traffic control centres across the country.

Officials cited “extraordinary circumstances” caused by communications problems at regional air traffic control centers, according to an FAA notice.

However, after a few hours, the airspace was reopened and the nationwide halt was lifted.

It was the first nationwide ground stop since January 2023, when a key FAA computer system malfunctioned. Before that the last time had been after the September 11, 2001, terror attack.

Reason behind the shutdown

US authorities have attributed the disruption to a telecommunications outage affecting air traffic control centres across the country, ruling out cyberattack, Microsoft link.

According to Transportation Secretary Sean Duffy, the disruption was caused by ageing hardware, while Homeland Security Secretary Markwayne Mullin ruled out any indication of a cyberattack and dismissed suggestions of a link to Microsoft’s recent service outage.

In a press briefing, Mullin said there was no indication that the disruption was the result of a deliberate attack or a threat to national security. “I want to make sure everybody understands that there is no connection between this and Microsoft. I know a lot of people are making that jump. So far, what we’ve seen is that there is actually no cyber attack. We’re still working through that process; our teams are working,” he said.

“Everybody’s safe. There’s no reason to be concerned about your loved ones if they’re flying,” Mullin said, AP reported.

Meanwhile, Duffy warned Americans traveling that getting planes back in the air may take time and that getting air traffic back to normal would be slow.

Profound consequences

The consequences were profound, disrupting potentially thousands of planned flights through at least late Friday night and upending travel plans for passengers.

“It’s frustrating. This certainly sounds like it’s going to be more than the usual run-of-the-mill delay. I look forward to finding out why,” Jeff Dubner, a Washington attorney whose Alaska Airlines flight home from Los Angeles was already half an hour late and taxiing to the runway when the plane came to a halt, told AP.

More ​than 4,700 flights were canceled and 10,000 delayed on Friday, while another 700 had already been canceled for Saturday, according to FlightRadar24. ​Aviation analysts said it could take days for airlines ​to restore their schedules after a nationwide grounding that lasted more ‌than ⁠four hours, Reuters reported.

Among the airports where many of the flights ended up being diverted are Chicago O’Hare International Airport, Denver International Airport, Dallas Fort Worth International Airport and Ronald Reagan Washington National Airport.

Some 11,000 flights carrying more than 1.5 million passengers were scheduled to take off from airports in the U.S. after 4 p.m. Eastern, raising the likelihood of more cancelations and flight diversions.