Rising heat threatens on-time departures as airlines grapple with thinner air

Extreme temperatures are forcing airlines to limit weight or delay flights because hot, thin air reduces lift and engine thrust.

Hot weather thins the atmosphere, diminishing both wing lift and jet-engine thrust, which can prevent planes from leaving the ground safely. Airlines respond by shedding weight—removing passengers, cargo, or fuel—or by postponing departures until temperatures drop. Airports situated at altitude or with limited runway length, like Denver International, New York's LaGuardia and Washington's Reagan National, are especially vulnerable.

Climate-change research forecasts that 10-30% of flights at certain hubs could encounter weight limits during the hottest part of the day by 2050 if emissions stay high. Recent incidents, including American Airlines compensating volunteers on a 114 °F flight out of Las Vegas and Delta asking for volunteers in a July 2023 heat warning, illustrate the emerging operational challenges. The FAA does not set a universal temperature ceiling; limits depend on aircraft type, weight and airport altitude. Experts warn that increasing heat waves and urban heat-island effects will make such disruptions more frequent.