The stair-stepped approaches to airports in use today begin many miles from the airport and require substantial time flying at low altitudes. Planes descend in steps and require additional thrust each time they level off. With CDA, an aircraft is positioned at its most efficient cruise altitude until it is relatively close to its destination airport. At that point, the aircraft reduces engine thrust to idle and begins a gentle descent to the runway. Benefits include significant reduction in noise, fuel burn and emissions, and shorter flights.