The United States Federal Aviation Administration (FAA) suspended takeoffs at all airports in the country this Friday (13). The measure was adopted due to a communications failure at air traffic control centers. The restriction was lifted four hours later.
According to the agency, the problem involved the telecommunications systems used to control flights. The American government is investigating the causes. President Donald Trump initially ruled out a relationship with cyber attacks or artificial intelligence.
The shutdown caused thousands of cancellations and delays. More than 13,000 flights were affected, according to The Wall Street Journal. The impacts are expected to continue over the weekend, as companies reorganize their operations.
The suspension also affected international flights to the United States. Authorities in Mexico and Europe adopted restrictions at the request of the FAA. The episode was the second national shutdown of takeoffs in the US since the attacks of September 11, 2001.
See what is known about the suspension of flights in the USA:
1. What caused the stoppage of flights in the USA?
There is still no definitive answer as to what led to the strike. The American government says it continues to investigate the details.
According to a statement by US Secretary of Homeland Security, Markwayne Mullin, a telecommunications problem caused the interruption of operations.
According to the CBS News network, the failure would have been caused by an update to the network operated by L3Harris, responsible for connecting air traffic control systems. The problem would have caused an interruption in communications.
A plane lands after the US Federal Aviation Administration (FAA) issued a nationwide ground flight suspension order "due to extraordinary circumstances and safety reasons." Ronald Reagan Washington National Airport, in Arlington, Virginia, USA — Photo: REUTERS/Jonathan Ernst
2. How many flights were affected by the suspension?
More than 13,000 flights were canceled or delayed due to the suspension of takeoffs, according to the American newspaper The Wall Street Journal.
In addition, more than 1.5 million passengers were scheduled to travel on flights that would depart after the restriction began. The estimate is from the aviation data analysis company Cirium, cited by The New York Times.
By 8pm (Brasília time), around 600 aircraft had been diverted to airports other than their original destinations. Most returned to the airport from where they had taken off.
Chicago's O'Hare International Airport recorded the highest number of diversions, with 28 flights. Next comes Denver International Airport, with 26.
3. Did the failure affect the entire American fleet?
No. Despite the national suspension, some international flights originating in the United States were able to take off.
According to records from the air monitoring platform Flightradar24, cited by The New York Times, aircraft departing from Boston and New York bound for Europe and Asia were allowed to leave the ground after delays.
4. Have international flights been affected?
Yes. The restriction had an impact on operations outside the United States.
The FAA asked Mexico's aviation authority to ground aircraft at Mexican airports with scheduled flights to the United States, the Mexican agency said this Friday (13).
In Europe, Eurocontrol, the organization responsible for coordinating air traffic on the continent, suspended flights originating in member countries and heading to the United States at the request of the FAA. According to a statement from the entity, the decision was taken because of technical problems.
5. When was the last time a strike of this type happened?
The last time the Federal Aviation Administration (FAA) suspended all takeoffs in the United States was in January 2023.
At the time, a failure in the agency's aeronautical information system caused the cancellation of more than 1,300 flights and delays in almost 10,000.
6. Are there any suspicions of a terrorist attack?
No. The United States Secretary of Homeland Security ruled out the possibility of an attack and stated that the episode is not a "new September 11" and that it is just a telecommunications failure.
7. Does the crash have to do with artificial intelligence?
The suspension of takeoffs in the United States occurred just days after the FAA expanded the use of an artificial intelligence system to assist in air traffic control. The tool, called SMART, began to be implemented in September and reached the country's 22 control centers on November 10, according to the specialized magazine Ars Technica.
The system analyzes meteorological data, flight routes and controller availability to suggest changes that reduce delays and improve aircraft circulation. The recommendations, however, remain under evaluation by agency professionals.
There is no official explanation that links the tool to the strike. The company Air Space Intelligence, responsible for developing the system, denied involvement in the failure. The American government is investigating the case, whose initial hypothesis points to a problem in telecommunications.
8. Does this case have anything to do with the problem involving Microsoft?
The President of the United States, Donald Trump, stated in an interview with Fox News that the suspension of flights does not appear to be related to a cyber attack or problems involving artificial intelligence.
Microsoft, which faced technical problems on Thursday (12), also denied any connection with the episode. In a statement, the company stated that "there is no indication" that the suspension of takeoffs is related to the company's services.
In a press conference at the White House, Homeland Security Secretary Markwayne Mullin also said there was "no reason" to link the outage to technological problems involving Microsoft.
Passengers wait at Logan International Airport after the U.S. Federal Aviation Administration (FAA) issued a nationwide ground flight suspension order "due to extraordinary circumstances and safety reasons," following an earlier agency report on serious communications problems in air traffic control, in East Boston, Massachusetts, USA, November 13, 2026 — Photo: Brian Snyder/REUTERS
9. Is there a forecast for normalization?
So far, the FAA has not announced when the suspension will end. The initial forecast was that the restriction would last until 22:00 UTC (19:00 Brasília time).
According to aviation analyst Robert Mann, in an interview with Reuters, if the suspension continues until the evening, it will probably be necessary to wait until the weekend to resolve the impacts on airline operations.
10. What do authorities and companies say in Brazil?
The National Civil Aviation Agency (Anac) monitors the situation and recommends that passengers consult the airlines to check possible changes to flights.
The agency also advises companies to immediately report any delays and cancellations and to keep passengers informed about expected departure times.
In case of delay or cancellation, re-accommodation must be free and may occur on the company's own or another company's first available flight.
If you prefer to travel on another date or time, the passenger can choose a flight from the airline itself, subject to the ticket's validity period.
GRU Airport received an alert to keep flights to or from the USA on the ground until further notice and advises passengers to contact airlines.
Gol reported that it monitors two flights departing from the USA, with a focus on safety. Azul awaits guidance. One of the company's flights was normally heading to Orlando, while three others were scheduled.
