Impact of Extreme Heat on Flight Operations

Airline passengers generally expect flight delays when facing thunderstorms, heavy snow, or strong winds. However, high temperatures can also disrupt flights significantly. On extremely hot days, thinner air can impede aircraft from safely taking off. Airlines may need to adjust the weight by reducing passengers, cargo, or fuel carried.

At airports in desert regions like the U.S. Southwest and the Middle East, this issue is prevalent. But it can also occur at airports with high elevations or shorter runways. Researchers note that climate change could make such disruptions more frequent.

Heat’s Effect on Aircraft Performance

This summer, heat waves have affected parts of the U.S. and Europe. In Las Vegas, American Airlines compensated customers who gave up their seats on a July 24 flight due to extreme heat, reaching 114 degrees Fahrenheit (47 degrees Celsius). This reduction in weight is standard practice in hot conditions to ensure safe takeoff.

According to Ross Aimer, a retired United Airlines captain and CEO of Aero Consulting Experts, hot air is thinner than cool air, affecting lift and engine thrust. He equates this effect to athletes competing at high altitudes where thinner air causes fatigue. Aircraft engines, like humans, perform better with cooler, denser air.

Preflight Considerations

Pilots and airlines evaluate several key factors before takeoff, including the aircraft’s weight, airport elevation, and outside temperature, as explained by Alan Price, a retired Delta Air Lines captain. In high-elevation airports like Denver, the air is already thin, so even moderately high temperatures can affect takeoff performance.

Runway length is crucial; planes need adequate distance to gain speed. Shorter runways, like those at New York’s LaGuardia, may lead to weight restrictions during hot weather. If calculations show unsafe departure conditions, airlines may adjust the load, reduce fuel, or wait for cooler temperatures.

Eventually, some conditions may prevent safe takeoff despite weight adjustments. Airports follow Federal Aviation Administration (FAA) guidelines, which vary based on aircraft specifications and conditions.

Frequent Delays Due to Rising Temperatures

A 2017 study projected that if greenhouse gas emissions rise, weight restrictions might affect 10% to 30% of flights at various airports by midcentury. Another study suggested that planes in Europe might need to reduce the weight of 10 passengers per flight by 2065.

Phoenix Sky Harbor International Airport now averages 43 days a year with temperatures above 110 F (43 C). Las Vegas sees about 18 such days, doubling past averages. Palm Springs International Airport noted an 83% increase in 110 F days since 2000.

Operational Adjustments by Airlines

Airlines have long managed these challenges. American Airlines canceled flights in California and Arizona in June 2016 and 2017 due to heat. In July 2018, Denver’s high temperatures led to passenger adjustments on flights.

In July 2023, Delta Air Lines sought volunteers to disembark a plane in Las Vegas because of heat-induced weight restrictions. The extreme heat can exacerbate issues due to the urban heat island effect, where airports become hotter than surrounding areas.

Jennifer Brady, a Climate Central data scientist, notes that airports’ lack of shade, heat-absorbing surfaces, and constant activity contribute to them being city hot spots.