The Department of Transportation Air Traffic Control Advisory Committee concentrated on control of aircraft through the airspace, from takeoff to landing. Emphasis was placed on major terminal areas and on the denser portions of the enroute airspace where the need for efficient use of scarce resources (principally runways and terminal airspace) and the danger of mid-air collisions make sophisticated air traffic control mandatory if safety is to be assured without sacrifice of capacity. Airports were included in the study insofar as they strongly interact with air traffic control, and then, primarily, the committee's concern was with efficient use of runways. No work was done on airport access. Considerable effort was placed on the subject of noise reduction which may be critical to community acceptance of high-capacity airports.