The control system, operational procedures, aircraft guidance, and basic runway design factors necessary to greatly reduce the lateral separation of independent operating parallel runways, and the longitudinal separation between approaching aircraft are discussed. Included are the basic performance characteristics required for the approach and landing systems. To obtain the necessary increase in runway utilization rates, a higher degree of automation will be required in the air traffic control system and in the airborne flight control system. In addition, a new approach and landing system which can provide curved approaches is proposed. The resulting capacities for various levels of automation, reduced separations, and runway configurations are listed.