Amsterdam's Schiphol airport says its fuel supply system has now restarted, hours after a fault led to major disruption.
At least 70 planes were grounded, and others diverted, when the airport's refuelling facility stopped working at around 13:00 (11:00 GMT) on Wednesday.
Thousands of passengers were stranded, and many spoke of chaos and a lack of information in the airport.
It is not clear when the disruption will be fully over.
Schiphol airport had earlier warned it could be "long into the evening" before things returned to normal.
It later said that flights had restarted:
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But it also urged travellers to contact their airlines.
The company supplying the fuel system, Aircraft Fuel Supply, said the failure of the system was not due to the current heatwave, the Dutch newspaper De Volkskrant reports.
The fault meant that only planes that had enough fuel on board were able to take off from the airport.
As well as the 70 grounded planes, passengers on a further 11 recently landed planes were unable to immediately disembark because there was no gate available, De Volkskrant reports.
Almost 180 flights had been cancelled by airlines, Schiphol said.
One British passenger, Michael Lowery, was at Schiphol waiting to catch his flight back to Norwich when the outage occurred. He told the BBC there was a four-hour queue for the airline KLM's information desk.
"It's been really awful service at the airport," he said. "They can't control the situation at all.
"The queue's stretching across the terminal and that's just for information. They won't book me a hotel unless I wait in the queue. So I either have to book one myself or wait four hours in a queue to maybe get one."
Others said they had problems finding a place to stay for the night.
Paul Hewitson, who had flown in from Inverness in Scotland for a connecting flight to the Norwegian city of Stavanger, said he was told by KLM they could not find a hotel room for him because everywhere was booked up.
He tried three hotels before he found a room. "I've got no bag, a £100 ($125) taxi bill and £180 hotel bill," he told the BBC.
July is one of the busiest periods for the airport as people fly off for their summer holidays.