Air travel in the US will soon be back to normal, a senior Trump administration official said on Sunday, after a nationwide ground stoppage rocked the country and caused headaches for international flyers.
Airlines rushed to restore regular schedules, leaving more than 6,100 flights cancelled and another 7,400 trips delayed as of Saturday night, according to aviation data firm FlightAware.
On Sunday, more than 1,540 flights were cancelled and more than 1,330 delayed.
Transportation Secretary Sean Duffy told ABC News that the US would "see things come back to normal today, fully normal tomorrow".
He told NBC News that he would not apologise for the ground stop, saying the problems stemmed from decades of neglect and underinvestment in the Federal Aviation Administration, predating his tenure.
"I can't apologise for what was passed on to us. And I can't blame Republicans or Democrats because it's all of them," he said. "It goes back 20, 25, 30 years of lack of investment."
FAA administrator Bryan Bedford did apologise for the disruption on Saturday.
“I do think the worst is behind us,” he said at a news conference. “But we still do have a significant amount of recovery work to do with our airline stakeholder group.”
Friday's ground stoppage was the longest in the US since the September 11, 2001 terror attacks and only the third in the country's history. It lasted for four hours, with authorities blaming a data overload for crippling air traffic control communications and radar.
Mr Duffy said the issue was traced to replacement of outdated copper wire at a remote location by L3Harris Technologies and that a router there started flooding the air-traffic control system with connection attempts.
“This was an FAA system that didn’t meet the moment,” Mr Duffy said. “Our contractor didn’t meet the moment, or the equipment didn’t meet the moment and caused the outages.”
The failure left airlines trying to rebuild schedules with aircraft and crew scattered away from their usual duty stations.
“It will take time to reset our operation, including the positioning of aircraft and crews," Delta Air Lines said.
Last year, Congress provided the FAA with $12.5 billion to carry out the modernisation effort, but Mr Duffy has said more money is needed. He initially requested an additional $30 billion but upped the request to $50 billion after Friday’s breakdown.
