EasyJet has said last month's drone disruption at Gatwick was a "wake-up call" to airports after it cost the airline £15 million and affected 82,000 customers.
The airline said it racked up £10 million in passenger compensation costs and £5 million in lost revenues after more than 400 of its flights were cancelled when the drone sightings brought Gatwick to a standstill just before Christmas.
EasyJet chief executive Johan Lundgren said he was "disappointed" the airport took so long to resolve the situation and reopen the runways.
But he added that flying the drones was a "criminal act and illegal activity".
"You can't always protect yourself from that, but it's a wake-up call and airports will be better prepared going forward," he said.
The drone sightings saw flights at Gatwick suspended on December 19, with the airport not full reopened until December 21.
Mr Lundgren said easyJet "did everything we could to help our customers affected by the incident".
"I am proud of the way our teams worked around the clock to mitigate the impact of the incident and looked after affected customers," he said.
'Lack of certainty'
Drone sightings at Gatwick airport in December caused more than 400 EasyJet flights to be cancelled.
Total revenues in the three months to December 31 lifted 13.7% to £1.3 billion, while passenger revenues rose 12.2% to £1.03 billion.
Passenger numbers in the quarter also increased, by 15.1% to 21.6 million.
EasyJet said it was "well prepared" for Brexit and had not seen an impact on passenger bookings ahead of March 29.
It added: "Both the EU and the UK have committed to ensure that flights between the UK and EU will continue in the event of a no-deal Brexit."
Mr Lundgren said: "For the first half of 2019, booking levels currently remain encouraging despite the lack of certainty around Brexit for our customers."
Nicholas Hyett, equity analyst at Hargreaves Lansdown, said: "The drone disruption at Gatwick in December means these results aren't quite what easyJet was hoping for at the start of the year, but it hasn't blown things too far off course."
"Fortunately Brexit disruption seems to be minimal so far, and while meeting full year expectations may be a bit more of a stretch from here, they're still very achievable," he added.