FAA Lifts Nationwide Ground Stop at 8:15 PM ET After More Than Four Hours, With Nearly 5,000 Flights Canceled

The FAA has lifted its nationwide ground stop. It canceled the order at 8:15 p.m. ET today, Nov. 13, after more than four hours, and airlines are now trying to untangle a mess that will last well past tonight.

Flight-data firm Cirium counted 11,000 flights scheduled to depart U.S. airports after 4 p.m. ET. About 600 flights were diverted, 104 of them to other airports, Cirium said. FlightAware data showed nearly 5,000 flights canceled in, out of or within the U.S. as of 7:20 p.m. ET, with more than 10,000 delayed.

Chicago O'Hare led the cancellation list with 251 at that point. Atlanta's Hartsfield-Jackson, the world's busiest airport, topped 200. More than 100 flights were canceled at major airports in New York, Boston, Texas and Denver.

Sources differ on exactly when the halt began. CNBC put the FAA's issuance of the ground stop at about 4 p.m., Business Insider reported a ground stop was called around 3 p.m. in one account and around 3:45 p.m. in another. Duffy posted on X just after 4:15 p.m. ET that the halt followed "a communication issue impacting all Air Route Traffic Control Centers."

Airlines Face a Weekend of Recovery

The FAA said flights would depart as en route traffic facilities recover, through coordination with the air traffic control system. A ground stop freezes planes at their departure point, so crews and aircraft end up in the wrong places. Disruptions snowball as crews hit their maximum duty hours.

JetBlue told staff in a memo it would cancel the rest of today's flights except European routes, plus others scheduled for Saturday, so crews and planes can get back in position. International flights began leaving coastal hubs before 6 p.m. ET.

Travel analyst Jamie Larounis said the disruption would likely ripple into the weekend. "This won't be a quick fix," he said.

United, Delta and Alaska issued waivers allowing changes without fees or fare differences. The Los Angeles Times reported that United would waive change fees and fare differences for passengers who reschedule onto a flight departing on or before Nov. 20. Federal rules entitle travelers to a refund if an airline cancels their flight, regardless of the reason. Airlines are not required to cover hotels or meals after an air traffic control outage.

The disruption also hit sports travel. According to the Associated Press, the Brooklyn Nets were stuck trying to get from New Orleans to Memphis. The San Jose Sharks' flight to Utah for Saturday night's game did not leave in time.

What Officials Say Caused It

Duffy said the FAA's data systems experienced "inconsistency" in communicating with aircraft. He and Homeland Security Secretary Markwayne Mullin blamed the age of the air traffic control system. Business Insider reported that the two called on Congress to provide $50 billion for modernization.

Duffy said the airspace is open but "it's going to take us some time to unwind what's happened." He also argued Congress has not funded system upgrades.

Mullin said there is "zero evidence" this was a cyberattack. He said it appears "mechanically driven" and that the public "was never in danger." President Trump told Fox News it does not look like a cyberattack because "there's nobody taking credit."

The FAA's own account has been narrower. It described a "temporary telecommunications outage" and said it halted flights out of an "abundance of caution." Its technicians are still investigating.

The AI Question

The outage came the same week the FAA deployed SMART, an AI tool for air traffic control. Asked earlier in the day whether it might be related, Mullin said, "That's what we're looking at." At the evening briefing he said he had seen zero evidence of a problem with artificial intelligence.

ASI, the company that makes SMART, said the failure was not "based on or a result of the SMART system, any product of ASI or our integration with FAA and ATC." Microsoft, which had service problems earlier this week, said it had "no indication" the ground stop was tied to its services.

A report relayed by The Guardian said the outages in communication, radio frequencies and radar began in Chicago. CNN, as cited by The Guardian, reported the FAA told airlines the outages were the result of router malfunctions believed to have originated at Chicago Midway airport. The FAA has not publicly named a root cause.

Political Fallout

House Democrats demanded answers while the administration struggled to explain the shutdown, with one asking, "What the hell is going on?" Democrats also pointed to Trump's silence on social media during the crisis. The administration's response is that the system is decades old and that Congress holds the purse strings.

Nationwide ground stops are extremely rare. CNBC described this as the second nationwide ground stop since the Sept. 11, 2001 attacks. The previous one came in January 2023, when the FAA halted flights because of issues with a pilot alert system, and it lasted only about 90 minutes.

In September, a Verizon fiber cable accidentally cut during construction in New Jersey caused hundreds of cancellations, delays and diversions at Newark and Philadelphia.

It is not yet clear what failed or why. Duffy cited data "inconsistency" and Mullin said it looks mechanical, but no root cause has been confirmed. Whether the money request gets traction in Congress will depend on that answer, and on how fast airlines clear the backlog before Sunday's NFL travel.