What phenomenon can follow aircraft in the form of disturbed air?

Wake turbulence refers to the disturbed air that is generated behind an aircraft as it moves through the atmosphere. When an aircraft flies, it creates vortices from the wingtips due to the difference in pressure between the upper and lower surfaces of the wings. These vortices are particularly strong in larger aircraft and can persist for some time after the aircraft has passed, creating a turbulent area that can affect other aircraft flying through it.

This phenomenon is crucial for pilots to understand because it can pose significant hazards, particularly during takeoff and landing phases. Smaller aircraft can be adversely affected when they encounter wake turbulence from larger ones. This disturbance can lead to loss of control or unintended altitude changes if another aircraft flies too closely behind or below a larger aircraft.

The other choices, while related to aerodynamics and flight, do not represent the primary phenomenon of disturbed air following an aircraft. Propwash primarily describes the airflow generated directly beneath a rotorcraft or fixed-wing aircraft during flight, thermal lift involves rising columns of warm air, and air pockets generally refer to sudden drops in altitude caused by variations in air density, not a sustained form of disturbed air like wake turbulence.