Aircraft noise is noise pollution produced by any aircraft or its
components, during various phases of a flight: on the ground while
parked such as auxiliary power units, while taxiing, on run-up from
propeller and jet exhaust, during take off, underneath and lateral to
departure and arrival paths, over-flying while en route, or during
landing.
Aircraft noise is the most significant cause of adverse community
reaction related to the operation and expansion of airports. This is
expected to remain the case in most regions of the world for the
foreseeable future. Limiting or reducing the number of people affected
by significant aircraft noise is therefore one of ICAO's main priorities
and one of the Organization's key environmental goals.