Thousands of weary passengers remain stranded at Gatwick airport, the UK's second busiest, for the second day on Friday as the Army was called in to help deal with the unprecedented crisis caused by drones, ahead of the busy holiday season.
As the airport resumed operations, British Transport Secretary Chris Grayling said there was no evidence it was terror-related.
By Thursday night, 120,000 people had their flights cancelled, the BBC reported.
Gatwick authorities said 765 flights were scheduled for departure and arrival on Friday.
Gatwick's Chief Operating Officer Chris Woodroofe said police had not yet found the drone operator. Police said it was possible they were an environmental activist.
He said extra "mitigating measures" from the government and military had given him "confidence to reopen" the airport.
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The airport is expected to be "back to normal" by the end of Saturday, media reports said.
"We are now operating at almost normal runway conditions and the challenge for the airlines, as the result of this disruption, is that their planes are not all in the right place," Woodroofe said.
"So what we'll be doing today is recovering their operations so by tomorrow (Saturday) we are back to standard operation and continue to recover the situation for our passengers."
Woodroofe added: "My intention is to get those passengers to their destinations so that they can enjoy their Christmas."