More frequent heat waves and rising temperatures caused by global warming could ground up to a third of aeroplanes worldwide, a study shows.
Airlines may increasingly be forced to cut their loads of passengers, cargo or fuel in order to take off safely because warming air lessens the ability of plane wings to generate lift, according to US researchers.
Worldwide, average temperatures are expected to climb some 3degC by 2100, researchers say.
But it is more prevalent heat waves that pose a larger threat to the airline industry, they said in a study published in the journal Climate Change.
Annual maximum daily temperatures at airports could rise by 4 to 8degC by 2080, they found, leading to more costly delays in take-offs or cancellations.
During the hottest parts of the day, between 10 and 30 percent of fully loaded planes may have to dump weight in order to begin their journey.
The phenomenon could force the aviation industry to brace for thinner profit margins, the authors say.
A full 160-seat aircraft trying to safely take off in searing heat may, for instance, need to remove 13 passengers.
But the costs of delays or cancellations could also disrupt other sectors of the economy as they trickle down.
Airports likely to be most affected according to the researchers' appraisal of 19 major airports include New York's LaGuardia, due to short runways, and Dubai International Airport in the United Arab Emirates, because of scorching heat.
Projections found the least affected airports included New York's John F Kennedy International Airport, London's Heathrow and Paris' Charles de Gaulle.
Previous research has found that changes in climate may also increase turbulence on flights, the researchers said.