Hot and high

In aviation, hot and high refers to the ability of an airplane to operate safely from airports in very warm climates and/or very high elevations.

Warm air has a lower density than average, and the air at high elevation also has a lower density than at sea level. A lower air density means a reduction of the amount of lift generated by the airplane wings. This means that aircraft need a longer takeoff run than usual.

As a consequence, particular models of aircraft can not operate from "hot and high" airports with profitable loads.