The deleterious effects of high temperatures and humidity on the performance of aircraft are exacerbated in many places around the world under climate change. Last year, in a Center for Climate and Security briefer, these effects were discussed for both rotary and fixed wing aircraft. They include reductions in take-off weight because of reduced lift and, longer take-off and landing distances. The result will be that military operations will be at higher risk of disruption or outright failure, particularly in those locations where longer over-water distances need to be traversed. Complementing the briefer is a recent study by Gratton et al. (2020) that collected and analyzed climate change effects on the operation of two types of commercial, civilian aircraft that are commonly used at Greek airports.