More flight delays in the US and beyond are expected over the coming days after a computer glitch in a safety system grounded thousands of flights on Wednesday.
Although normal air traffic operations are slowly resuming, disruption will continue as airlines try to get planes in and out of crowded gates and the rescheduling of staff working hours affects timetables.
In total, nearly 10,000 flights within, into or out of the US were disrupted as authorities tried to restore the Notice to Air Missions (NOTAM) system, which alerts pilots of potential hazards along a flight route, changes to airport facilities and other essential information.
"What I was told over the phone is that it's like a 9/11 situation with the full ground stop," explained Tammara Williams, a traveller from Charlotte, North Carolina.
"And so when they said that, it immediately triggered something in my mind because I flew on the morning of 9/11. So my first thought was to get to the airport as quickly as possible," she added.
President Joe Biden has ordered the US Department of Transport to conduct a full investigation after dismissing a cyber attack. The latest information says the outage was caused by damage to a database file.
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