The chief executive of EasyJet said the low-cost airline had stabilised it flight operations after cutting its summer schedule last month, but melting runways and air traffic control (ATC) restrictions were not helping during a "challenging summer".
CEO Johan Lundgren said easyJet's daily operations were back to pre-pandemic levels after the cuts, which followed caps on capacity at London Gatwick and Amsterdam's Schiphol Airport.
"We can't help if runways are closed down because they're melting, we have help if air traffic control puts restrictions into the flow system," he said at the Farnborough Airshow on Tuesday.
"But the things that actually are within our control, that's been stabilised."
Flights at Britain's London Luton Airport were temporarily disrupted on Monday after soaring temperatures caused a defect in its runway, prompting airlines including easyJet to divert planes.
Lundgren said easyJet had removed a row of seats in its A319 aircraft to free up a member of cabin crew and had deployed more staff in airports to increase resilience.
"Having said that, we can't be complacent because we know that there are challenges around the ATC environment, ground handlers, airports," he told Reuters.
Lundgren said he backed airports capping flights, adding that easyJet's cuts were in line with the moves.
"We were supportive of (a cap), because clearly the airport is in the best situation to evaluate what the whole of the system can deliver, in terms of ground handlers as an example," he said.
"For the sake of the customer, it is the airport who has the best view of the situation.
"One ground handler who fails working with one other airline will impact us as well because there will be delays."
The imposition of a passenger number cap at London's Heathrow, which is not used by easyJet, caused a row with Dubai's Emirates last week.
The airline's president Tim Clark, speaking at Farnborough, criticised Heathrow managers for failing to anticipate the travel rebound until it was too late.
EasyJet announced at the show it would partner with aero-engine maker Rolls-Royce for ground tests of hydrogen combustion engine technology.
Lundgren did not specify how much the airline would invest beyond saying it was a multi-million pound sum.