Aviation Terms->Controlled Airspace Aviation term used to
describe airspace in which ATC has the authority to control air
traffic, the level of which varies with the different classes of
airspace. Controlled airspace is established mainly for three
different reasons: 1- high-volume air traffic areas (e.g. near
airports), 2- IFR traffic under ATC guidance, 3- security.
According to the airspace classes set by ICAO, Class A, B, C, D,
and E airspace are controlled. It is the opposite of
uncontrolled airspace.