On Friday, the US Federal Aviation Administration (FAA) stopped all departing flights across the country.
The reason was a communication problem at regional air traffic control centres.
The FAA is the US agency that manages civil flights and air traffic safety.
It imposed a nationwide ground stop, which means planes cannot take off until the order is lifted.
The agency said the step was taken for safety reasons.
Key points
- On Friday, the FAA halted all departing US flights because of a communication outage.
- Flights already in the air were allowed to continue their journey.
- By Friday evening, more than 10,000 flights were delayed and about 4,000 cancelled.
- The FAA has since lifted the ground stop, and airlines are restoring normal schedules.
So what caused the outage?
US Transportation Secretary Sean Duffy said FAA technicians were investigating the problem.
Later, he said old equipment was the main cause.
He said switches and routers became overloaded and shut down. They then began giving inconsistent data.
Officials said there was no sign of a deliberate attack or cyberattack.
What does this mean for travellers, including Indians?
Airlines said international departures would be handled case by case.
Passengers flying to or from the US faced long delays and cancellations.
If you have a flight to the US, check your flight status before leaving home.
Airports may still see crowds as the backlog clears.
Sports teams also had to rush to reach their cities before weekend games. The disruption touched NBA, NHL and college teams.
What happens next for airlines and passengers?
The FAA has lifted the ground stop, and the first aircraft took off from Chicago O'Hare Airport after nearly four hours.
Airlines are now working to clear the backlog.
Duffy has blamed Congress for not funding a new system that he says could prevent such outages.
He has called for $50 billion to modernise it.
Earlier, the White House and the Department of Transportation had asked Congress to approve $30.1 billion for airports and air traffic control upgrades.
Graphic: News Anek, from the facts in this report
Sources
- Free Press Journal: US Flights Grounded Nationwide After FAA Communication Outage; Airlines Warn Of Widespread Travel Disruptions
- Hindustan Times: US flights grounded LIVE: Thousands of passengers stranded, many may have to sleep at airports, says official
- Lokmat Times: US Flights Grounded Nationwide Due to Air Traffic Communication Outage
