Resumption of traffic, thousands of canceled flights, “old equipment” involved… What we know about the suspension of flights in the United States

The United States reopened its airspace on Friday after several hours of suspension of takeoffs, caused by a communication problem. “At 8:15 p.m. Eastern time, we reopened the airspace,” Transport Minister Sean Duffy said at a White House press conference, blaming “old equipment” from the “1980s” for the cancellation of thousands of flights. However, the return to normal will be slow, he warned. Homeland Security Minister Markwayne Mullin added that there was “no cyberattack” and “no connection” to the major outage that hit Microsoft on Thursday.

This suspension of flights was taken by the American aviation regulator (FAA) following “communication problems” affecting several air traffic control centers. The FAA, whose blocking order had been relayed by Sean Duffy on his X account, had specified that its technicians were working to determine the origin of the problem.

The regulator added on “Each flight has been recorded and international flights will be managed on a case-by-case basis,” he said. The FAA also mentioned “exceptional circumstances”. “All departing traffic must remain stopped on the ground until further notice,” the government agency’s official notice said, adding that landings of incoming international flights would be managed on a case-by-case basis. According to flight tracking tool FlightAware, 9,000 flights were delayed and more than 6,000 canceled this Friday. In total, 30,000 departures and arrivals were planned for the rest of the day when the notice was published. In press releases, both United Airlines and American Airlines indicated that current flights were continuing, but that no new flights would take off as long as the grounding measure remained in effect.

This suspension decision was not due to a threat to the United States, Minister of Homeland Security Markwayne Mullin immediately affirmed. “This is not a new September 11,” the minister declared to the press at the White House, refusing, however, at this stage to rule out any possibility, including that of a cyberattack. “There is no indication at this time that this is a malicious attack against us. It’s simply a telecommunications outage at the moment,” he added, asserting that “Donald Trump has been informed” of the situation. “It’s going to take time. But, again, everyone is safe. All thefts are traced and there is no reason for the public to be concerned.”

The FBI, which quickly ruled out the possibility of a cyberattack, said it was investigating to “determine whether a software update was the cause of the major outage.” Microsoft, for its part, affirmed that the immobilization of the planes was not linked to the outage of its Outlook services, which occurred on Thursday. Radars and radio frequencies were affected by outages at the same time, according to CNN. The National Weather Service also reported communications and internet problems, although it was unclear whether this was linked to the FAA outage.

The grounding order in any case had effects at airports in neighboring countries. That of Pearson, in Toronto, informed that it would not receive any flights from the United States this Friday. While in Mexico City, Benito Juarez International Airport urged travelers to check their flight status as some flights were affected.

Friday afternoon, for passengers at San Francisco airport, the news had broken on the way. And since then, the crowd had continued to grow in front of the doors. Many travelers had the phone in hand to give news to their loved ones. “For now, people are waiting. We have not received any official information, apart from what we see in the media,” Marie*, stuck in the boarding area and whose flight to Paris was due to take off at 3:10 p.m. local time, told Le Figaro. The only indication: a message from the crew, which reported any new points at 4:30 p.m. “Additional delay for this flight. We will keep you informed at 4:30 p.m. as soon as we have more information. Once again, due to the national shutdown of takeoffs, we anticipate an additional delay,” the crew announced to passengers.

Steve, who works in tech in San Francisco, was also waiting with his wife and their two children, aged two and five. The family was due to fly at 4:40 p.m. to London, where they planned to spend a few weeks with their family. She had learned of the grounding of flights on the way to the airport and had not planned anything for the children. “I remain optimistic. We’re going to wait, buy water and if it lasts we’ll go home,” confided the father, before adding: “It’s crazy, this hasn’t happened since September 11, which worries me a little.”

This suspension of flights took place on the same day as the White House requested Congress for an additional $30.1 billion in funding to modernize the air traffic control system in the United States. The Trump administration had already presented in May 2025 a plan for “complete modernization” of the air traffic control (ATC) system, some of which dated from the 1960s or still used floppy disks.

Friday's outage also came just days after the FAA announced the nationwide deployment of an artificial intelligence tool, SMART, intended to help air traffic controllers avoid delays. The company Air Space Intelligence (ASI), which designed the tool, denied being at the origin of the problem: “The current suspension of takeoffs is neither linked to the SMART system, nor caused by it, nor by any other ASI product or by the integration of our technologies with the systems of the American Federal Aviation Agency (FAA) and air traffic control (ATC).”

The SMART tool had been presented for the first time two months earlier in airports in the Washington region. That day, hundreds of flights were also grounded due to communication problems with air traffic control services. An electrical fault caused a system outage and it was discovered that contractors had accidentally cut a fiber optic cable that was intended to serve as a backup.

Air traffic controllers depend on constant communication with pilots to manage their flights. Without reliable communication, allowing planes to take off is risky. Before publishing its notice, the FAA suspended flights at O'Hare and Midway airports in Chicago, citing "equipment problems."

This is only the third time that the FAA has ordered the grounding of all flights nationwide: the first time was on September 11, 2001, following the terrorist attacks on the World Trade Center in New York, and the second time on January 11, 2023, due to a failure of the alert system intended to inform pilots of safety problems. This immobilization of 2023 had lasted some 90 minutes. Friday's lasted more than four hours.