What do we know about stopping flights in the United States, and what are the rights of travelers?

The US Federal Aviation Administration has lifted the longest nationwide grounding of flights since the terrorist attacks of September 11, 2001.

The administration said that the suspension of takeoff on Friday, which lasted more than four hours, came “due to exceptional circumstances” resulting from a communications problem that affected all air traffic control centers.

Homeland Security Secretary Markwayne Mullen said there were no signs of an attack and that everyone was safe.

Here's what we know.

How many flights were affected?

The grounding led to the delay of more than 8,500 flights and the cancellation of about 8,000 flights on Friday, according to the FlightAware website.

The Federal Aviation Administration said, in its first announcement at 15:54 EST (20:54 GMT), that all flights departing from within the United States will be prohibited from taking off until further notice.

More than 3,500 aircraft were in the air at the time. Some of them were diverted to other airports, while other planes continued their flights to their destinations.

Hours later, some flights were allowed to take off from San Francisco International Airport.

The Federal Aviation Administration reopened the airspace at 20:15 EST.

What about international flights?

All flights to the United States from Eurocontrol member states have been suspended “at the request of the Federal Aviation Administration due to technical issues,” according to the organization’s website.

Eurocontrol includes 42 member states, including dozens of European Union member states, the United Kingdom, Ukraine and Turkey, as well as Israel and Morocco.

Sydney Airport, the largest international airport in Australia, has suspended the takeoff of all flights bound for the United States until further notice.

Air Canada canceled flights between the United States and Canada.

When will air traffic return to normal?

The disruption will have ripple effects for a few days, Transport Minister Sean Duffy said at a news conference on Friday evening.

"We're going to need some time to process what happened this afternoon," Duffy added.

He said tens of thousands of people were stuck in airports across the country, many of whom "don't know where they will sleep tonight."

Delta Airlines and United Airlines said they had begun resuming operations.

American Airlines said it was "focusing on operating as many remaining flights as possible this evening." JetBlue said it would resume its flights on Saturday morning.

What are the rights of air passengers?

In the US, UK and EU, airlines may be obligated to pay compensation if the cause of the delay is deemed to be within their control, such as aircraft malfunction or pilot illness.

Airlines do not have to provide compensation to passengers because they were not responsible for the malfunctions in FAA systems.

But passengers are still protected under U.S. federal and state-specific laws.

Under the FAA Reauthorization Act of 2024, passengers must be offered alternative travel arrangements for canceled or “significantly delayed” flights — three hours for domestic flights and six hours for international flights — or a full refund if the passenger chooses not to travel.

The law also requires all airlines to refund tickets purchased with credit cards within seven working days of submitting the request, and within 20 days for tickets purchased by other means of payment.

If the passenger accepts a new flight offered by the airline, he will not be able to refund the ticket value.

In the United States, airlines are not required to provide meal vouchers or cover accommodation costs, but some may offer free assistance to customers.

However, if passengers are traveling from the UK to the US or on a flight operated by a UK airline, they may have additional rights.

Airlines

This includes providing meals and accommodation, if necessary, and transporting you to your destination. The airline should arrange for you to travel on an alternative flight at no additional cost.

Under British law, airlines have a duty of care to you when flights are delayed or cancelled.

The reason for delay or cancellation does not matter. Therefore, anyone affected by delays in air transportation will be covered by these rights.

What is the reason for stopping flights taking off?

Duffy said an old air traffic control communications system was overloaded.

“It's analog communications,” he added. “Our network switches and routers literally got overloaded and stopped working.”

He said that this affected communications and radar, and that the system needs a comprehensive modernization, estimating its cost at about 50 billion dollars.

“It will continue to be disrupted,” he added.

Homeland Security Minister Markwayne Mullen said during the press conference that they had detected “absolutely no evidence” that what happened was a cyber attack.

He also ruled out any connection to the global outage that struck Microsoft and began on Thursday.

Mullen said that introducing some new technologies to an old air traffic control system led to it being overloaded.

The two ministers stressed that people's safety was not at risk at any time during the takeoff halt.

When was the last time flights were stopped?

This was the second nationwide moratorium of its kind since the one that immediately followed the plane hijackings carried out by Al-Qaeda on September 11, 2001.

A malfunction in 2023 meant that air traffic safety notices could not be disseminated, and flights were prevented from taking off until the system was restored.