Key facts
- Extreme heat reduces air density, making it harder for airplanes to achieve safe takeoff speeds.
- Airlines may reduce aircraft weight by removing passengers, cargo, or fuel to compensate for hot conditions.
- Climate change is projected to increase the frequency of such flight disruptions.
- Airports with higher elevations or shorter runways are more susceptible to heat-related takeoff issues.
- Studies suggest a significant increase in flight weight restrictions at various airports by midcentury due to rising temperatures.
Extreme heat is increasingly causing flight delays and disruptions, a phenomenon well-known in desert climates but also affecting airports with higher elevations or shorter runways. On hot days, thinner air makes it more difficult for aircraft wings to generate sufficient lift and for jet engines to produce adequate thrust for takeoff. This can force airlines to reduce the aircraft's weight by removing passengers, cargo, or fuel, or to delay flights until temperatures decrease.
Ross Aimer, CEO of Aero Consulting Experts, explained that the science of flight dictates that jet engines require cool, dense air for optimal performance, likening the effect to athletes competing at high altitudes. Retired Delta Air Lines captain Alan Price noted that pilots and airlines must consider aircraft weight, airport elevation, and outside temperature for safe departures, with shorter runways and higher elevations exacerbating the issue.
The Federal Aviation Administration does not set a universal maximum temperature for takeoff, stating that operating limits are specific to each aircraft model, its weight, and the airport's altitude. However, research indicates a growing problem: a 2017 study projected that by midcentury, some airports could face weight restrictions on 10% to 30% of departing flights during peak heat if greenhouse gas emissions continue to rise. More recent studies suggest European airports may need to shed the weight equivalent of 10 passengers per flight by 2065.
Cities like Phoenix and Las Vegas are experiencing a significant increase in days with extreme heat. Phoenix has averaged 43 days annually above 110 F since 2020, a surge compared to previous decades. Las Vegas has seen its average number of such days more than double since the mid-20th century, and Palm Springs has recorded an 83% increase in days above 110 F this decade compared to the 2000s.