For a little over four hours on a Saturday, the American sky went quiet, as no domestic flight was permitted to leave the ground anywhere in the country. The FAA's decision to lift the halt at 8:15 p.m. Eastern ended the longest such pause since the attacks of September 2001, but its aftermath will ripple across airline schedules for days. The official explanation points to aging machinery whose switches and routers buckled under a load no one has fully explained, a reminder that even the most advanced society depends on old hardware it has been slow to replace. Whether the fault lies in the e
US Air Travel Resumes After Longest Nationwide Shutdown Since 9/11 Caused by Communications Failure
Over 1.5 million scheduled passengers were affected by thousands of cancelled and delayed flights, with some Dublin–US flights also disrupted.
"Give us the money to fix it."
Mark
Why does this one stand out from other outages?
Mimi
Scale and length. It's the longest nationwide ground stop since 2001, over four hours. The only other since then was about 90 minutes in January 2023.
Mark
What actually failed?
Mimi
Officials say switches and routers overloaded with data and went down. Sean Duffy called it old hardware.
Luke
Worth noting that's the Transportation Secretary's account. Why the equipment overloaded isn't known yet.
Mark
And the cyberattack question?
Mimi
Homeland Security says no signs of one, and Markwayne Mullin said zero evidence so far, adding it appears mechanical.
Luke
But he also said they're still looking, and neither a cyberattack nor a rogue AI system has been formally ruled out. That's an early read, not a conclusion.
Mark
Is the funding argument connected?
Mimi
The request for $30.1bn came the same day, and Duffy wants $50bn. But Congress already approved $12.5bn in July 2025, and the GAO says planning is fragmented, with 11,389 separate schedules.
Luke
So the link between this outage and the funding gap is Duffy's framing. The cause is unconfirmed, so it's not yet shown that money would have prevented it.
Mark
What about travellers?
Mimi
Over 1.5 million were scheduled to depart after 4pm ET, and Dublin–US flights face delays and some cancellations.
Luke
The cancellation and delay figures come from FlightRadar24, and the passenger number from Cirium, so they're third-party tallies, not official counts.
El Pulso
- More than 6,600 flights were cancelled and 8,600 delayed as a nationwide ground stop froze domestic departures for over four hours.
- Officials blame overloaded 'old hardware', while investigators have not ruled out a cyberattack or a rogue AI system.
- Transportation Secretary Duffy is pressing Congress for $30.1bn in airport and air traffic control upgrades, arguing the system is dangerously outdated.
- Full capacity will take time, with the FAA's modernisation running to 2028 and warnings that repeated delays could persist.
- Ripples reach Ireland, as Dublin Airport and Aer Lingus prepare for some cancellations and delays on US-bound and US-origin flights.
For a little over four hours on a Saturday, the American sky went quiet, as no domestic flight was permitted to leave the ground anywhere in the country. The FAA's decision to lift the halt at 8:15 p.m. Eastern ended the longest such pause since the attacks of September 2001, but its aftermath will ripple across airline schedules for days. The official explanation points to aging machinery whose switches and routers buckled under a load no one has fully explained, a reminder that even the most advanced society depends on old hardware it has been slow to replace. Whether the fault lies in the equipment, the funding, or the planning remains the question that will shape what comes next.
For more than four hours on Saturday, no domestic flight could leave the ground anywhere in the United States. The Federal Aviation Administration lifted the nationwide ground stop at 8:15 p.m. Eastern, ending the longest such shutdown since 11 September 2001. By then, more than 6,600 flights had been cancelled and 8,600 delayed, and over 1.5 million passengers had been scheduled to depart US airports after the halt began.
Transportation Secretary Sean Duffy blamed "old hardware," saying switches and routers had been overloaded with data and failed. What triggered the overload was not yet clear, and he warned that full capacity would be slow to return. The Department of Homeland Security said there was "zero evidence" so far of a cyberattack or rogue AI, though investigators had not ruled either out.
The outage landed amid a long strain of equipment failures, controller shortages and ageing infrastructure. The same day, the administration asked Congress for another $30.1 billion for airports and air traffic control, and Duffy blamed lawmakers for delays in funding a new system. Earlier money has been approved, but oversight reports warn that swapping copper for fiber alone will not prevent future outages.
The effects reached Ireland, where Dublin Airport expected some delays and a small number of cancellations on US routes, and Aer Lingus began clearing held flights to depart. The cause of the overload, the investigators' final findings and Congress's response remain the things to watch.
For more than four hours on Saturday, no domestic flight could leave the ground anywhere in the United States. The Federal Aviation Administration lifted the nationwide ground stop at 8:15 p.m. Eastern Time (0115 GMT), ending the longest such shutdown since the attacks of 11 September 2001.
The damage was already large. According to FlightRadar24, more than 6,600 flights were cancelled and another 8,600 delayed, with 1,500 flights already cancelled for Sunday. The aviation analytics firm Cirium said over 1.5 million passengers were scheduled to depart US airports after 4pm ET (2100 GMT), shortly after the ground stop began. Analysts said a grounding of this length could disrupt airline schedules for days.
Transportation Secretary Sean Duffy, speaking at a White House press briefing, blamed "old hardware." He said switches and routers had become overloaded with data and went down. What caused them to overload was not immediately clear. He cautioned that air traffic operations would take time to return to full capacity. "It's going to be slow," he said.
The question of a cyberattack hung over the day. The Department of Homeland Security said there were no signs the outage was caused by one. Homeland Security Secretary Markwayne Mullin said there was "zero evidence" so far of a cyberattack or a rogue AI system, though investigators had not ruled out either. "It appears this was mechanically driven. However, we're still looking," he said. The National Security Agency is working with Homeland Security on the investigation.
The timing was pointed. The same day, the White House and Transportation Department asked Congress for another $30.1 billion (€27.3bn) to upgrade airports and air traffic control, including $10.1bn for air traffic control modernisation. Duffy blamed Congress for failing to fund a new system he said could prevent such outages, and called for $50bn to modernise it. "What we have is an incredibly old air traffic control system," he said. "Give us the money to fix it."
The only other nationwide ground stop since 2001 came in January 2023, when the FAA halted domestic departures for about 90 minutes. This one ran well beyond that, and it arrives amid existing strain: equipment and communications problems, controller shortages and ageing infrastructure. A 2024 Government Accountability Office report found the FAA had classified 51 of its 138 air traffic control systems as unsustainable and another 54 as potentially unsustainable.
September offered a preview of how failures compound. After error messages appeared on a telecommunications circuit serving a Philadelphia air traffic control facility, the FAA's contractor switched to a backup fiber-optic line. A construction crew then accidentally severed that line in New Jersey. About 9,500 US flights were delayed or cancelled that day.
Money has been approved before. Congress provided $12.5bn in July 2025 for modernising air traffic control, including telecommunications and radar. The administration says 68% of the FAA's legacy copper telecommunications network has been replaced with high-speed fiber. But an FAA official warned in September that swapping copper for fiber alone would not prevent future outages without a modern telecommunications network. The GAO also said in September that the FAA lacked a reliable cost estimate and an integrated master schedule; as of May it had 11,389 separate, uncoordinated project schedules, raising the risk of repeated work at the same facilities, delays and cost overruns. The FAA aims to finish the first phase by December 2028, and the GAO warned that poor planning could leave the agency relying on failure-prone systems for longer.
The effects reached Ireland. Dublin Airport said some delays on flights between Dublin and the US were expected and a small number of scheduled flights would likely be cancelled. Aer Lingus said some of its flights from the US, previously held, were being cleared to depart, and it will contact affected customers directly. The Department of Transport called it an evolving situation and advised anyone due to travel to the US on Saturday 14 November to check with their airline.
The cause of the overload, the final word from investigators, and Congress's response to the funding request are the things to watch next.
Citas Notables
What we have is an incredibly old air traffic control system. Give us the money to fix it.— Sean Duffy, US Transportation Secretary
It appears this was mechanically driven. However, we're still looking.— Markwayne Mullin, Homeland Security Secretary
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