Nationwide US flight ground stop: what we know about the communications failure

The US Federal Aviation Administration (FAA) halted departures across the United States on Friday 13 November 2026. According to TVN24, it was the largest halt to air traffic nationwide since the attacks of 11 September 2001. Before this, similar orders were issued in 2001 and in January 2023, making it only the third such nationwide order in US history.

What happened

According to an FAA statement, the ground stop was in effect from 3.54pm Eastern Time, and flights resumed after more than four and a half hours. Some outlets put the length of the halt at close to five hours. Thousands of flights were cancelled or delayed over Friday and Saturday, though the figures vary by source.

Polish airline LOT had three return flights to Warsaw at the time. All of them departed, with delays ranging from a few minutes to more than four hours. The airline also said flights LO65 from Warsaw to Bangkok and LO23 from Warsaw to Los Angeles could be delayed by around two hours.

What investigators have found so far

Transport Secretary Sean Duffy described a failure in an ageing, analogue communications system, including communications devices, switches and routers, which became overloaded with data during an update. The problems affected 17 of the 22 regional air traffic control centres. Duffy said the routers being replaced were around 25 years old, and that their replacement had been planned as far back as 2006.

According to rp.pl, L3Harris was carrying out routine maintenance on the day, replacing old copper cabling with fibre-optic lines in at least one location. Duffy initially ruled out a cyber-attack and an artificial intelligence tool as the cause, and the investigation is ongoing.

Officials at the Department of Homeland Security said there was no indication of a cyber-attack or of involvement by a foreign actor. They also said the incident was not linked to any Microsoft service outage.

What this means for you

People in the UK planning to fly to the United States, or to connect through a US airport, should check their flight status directly with the airline. The Polish government's travel portal Odyseusz advises Polish citizens to do the same before departure. It also notes that delays or cancellations may still occur.