The data showed that as the temperature increased, air density decreased, causing takeoff speeds to slow down. Over time, this has had a clear effect on air travel. For the turboprop aircraft at airports, the researchers charted that the average takeoff distance is 328 feet (100 meters) longer now than it was in 1974. This can present real problems for terminals that use shorter runways.

Guy Grafton, associate professor of aviation and the environment at England's Canfield University and one of the authors of the 2020 study, asserts that many Traffic Controllers may not have been aware of this effect. I don't think that most are noticing the trends of climate change because their job is to plan each day's flights based upon the latest observations and forecasts. You really need to observe changes over at least a decade, as we did with our paper, before the average impacts become noticeable and significant.

Aside from lengthening runways, air travel experts have to drop vehicle weights to fight the air density problem. This likely means reducing the number of passengers and the amount of cargo allowed on an aircraft. The 2020 study found that at airports, the maximum allowable takeoff mass was reduced from about 165,350 pounds (75,000 kilograms) in 1974, to 152,000 pounds (69,000 kilograms) in 2017. That's an 8 percent drop in carrying capacity over time. In the case of heatwaves, we've already seen airlines have to cancel tickets or ground flights entirely as a result of the hot air.