Flights have been cleared to resume across the United States after a nationwide ground stop caused by communications problems, which also disrupted services to New Zealand.
The Federal Aviation Administration (FAA) lifted the shutdown after temporarily halting departures over safety concerns, with the outage affecting 22 regional air traffic control centres.
It was the first ground stop since January 2023, when a key FAA computer system malfunctioned. Before that the last time had been after the September 11, 2001, attacks.
Air New Zealand confirmed flights from the US to New Zealand had been delayed as a result of the outage.
"We've proactively delayed these services by two hours as a precaution while we assess the situation," the airline said in a statement.
"We don't have any flights scheduled to depart New Zealand for the USA until this evening, and there is currently no impact to these services."
Air New Zealand said affected customers would be contacted directly and urged travellers to monitor the Air NZ app and website for updates.
Qantas had also confirmed the ground stop caused a "small number" of delays to its flights. One Qantas flight from JFK to Auckland had been delayed overnight.
"We have additional flexibility for customers who wish to change their flight departing to or from the US on 13 and 14 November local time," the airline said in a statement.
The US' top homeland security official attributed the problem to a telecommunications outage and said there was no indication the communications failure was related to a cyber-attack.
The consequences were profound, disrupting potentially thousands of planned flights and upending travel plans for passengers.
"It’s frustrating. This certainly sounds like it’s going to be more than the usual run-of-the-mill delay. I look forward to finding out why," said Jeff Dubner, a Washington attorney whose Alaska Airlines flight home from Los Angeles was already half an hour late and taxiing to the runway when the plane came to a halt.
Friday's restrictions were imposed "due to extraordinary circumstances and for reasons of safety," according to an FAA notice. The agency was investigating a communication issue affecting the 22 regional air traffic control centres that direct planes en route between airports nationwide, said Transportation Secretary Sean Duffy.
International flights were being handled on a case-by-case basis, according to Homeland Security Secretary Markwayne Mullin, with some seen taking off Friday evening. Meanwhile, some flights within Alaska and Hawaii were not impacted, Alaska Airlines said.
US Secretary of Homeland Security Markwayne Mullin said there was no indication yet that "this was a nefarious attack against us. It's just a telecommunications outage".
"Everybody's safe. There's no reason to be concerned about your loved ones if they're flying," Mullin said.
At least 827 flights were diverted as a result. As of 7.05pm EST, 670 flights were sent back to the airport from where they originally took off, while 157 were redirected to a different airport, according to Cirium, an aviation analytics company.
The airports where many of the flights ended up being diverted included Washington Dulles International Airport, Los Angeles International Airport, Cincinnati/Northern Kentucky International Airport and Nashville International Airport.
The problem appeared similar to a regional air traffic control communication outage in September that snarled hundreds of flights across the Northeast, aviation safety expert Steve Arroyo said, except this time on a nationwide scale. It may be linked to the outdated technology used by air traffic controllers.
"If you don’t have that ability, whether it’s because the old wires that they have are just run down or for whatever reason, you’ve got to stop aeroplanes on the ground," said Arroyo, who is a former United Airlines pilot.
"And not put them in the air where you’re going to risk not being able to communicate with them."
Saturday's ground stop was different from the one after September 11 because planes were not being told to land immediately, and pilots likely were able to communicate with ground controllers at airports, Arroyo said.
Auckland businesswoman stuck in Houston
Juanita Neville told 1News she was travelling to a girls' weekend in Nashville, but was now stuck in Houston airport.
"Flights now being cancelled everywhere. Just heard a flight is going to Australia. I’m staying in Houston for the night as I’m struggling to rebook."
She said airport staff had been "pretty good" at keeping passengers informed, providing updates about every 20 to 30 minutes.
"Everyone around me is pretty glued to their phones and looking at all the news outlets to see if they can get any updates," she said.
Neville said there had also been an announcement asking ground crew to report to a meeting point.
- Additional reporting by Associated Press
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