Extreme heat from human-caused climate change could make flight delays more common. Here’s why

Thinner air on the hottest days can make it harder for planes to take off. Airline passengers know to expect possible flight delays when weather forecasts call for thunderstorms, heavy snow, or strong wind. The omens are less obvious on a hot summer day with clear skies.Yet extreme heat also disrupts flights and travel plans. On the hottest days, thinner air can make it harder for aircraft to get off the ground safely. Airlines may have to lighten the load by removing passengers or cargo, or carrying less fuel.The snag is well known at airports in desert climates around the world, from the U.S. Southwest to the Middle East. But even less extreme heat can create similar challenges at airports with higher elevations or shorter runways. Researchers say human-caused climate change could make such disruptions more common.With heat waves searing parts of the United States and Europe this summer, Las Vegas illustrated how extreme heat can interfere with air travel. American Airlines offered compensation to customers who voluntarily gave up their seats on a July 24 flight from Harry Reid International Airport after the temperature reached 114 degrees Fahrenheit (47 degrees Celsius).The airline described reducing a plane’s weight as a standard industry practice in hot-weather destinations when conditions require it to ensure a safe takeoff. The explanation comes down to physics.Hot air is thinner than cool air, making it harder for a plane’s wings to generate lift and for jet engines to generate the thrust needed for takeoff, explained Ross Aimer, a retired United Airlines captain and CEO of Aero Consulting Experts.“There is a science behind all this,” Aimer said. “You can’t deny the science of flight and what it takes for an airplane to operate.”