There are several ways of judging the efficiency with which a terminal area is organised. Commercial operators are interested in the cost of the deviations or delays which they are subject to when using the principal terminal airports. Other users of the air space are concerned with the restrictions which terminal area procedures impose on their movements; while ATC (Air Traffic Control) authorities are interested in the cost of the ground facilities necessary to move the traffic with safety and expedition. In this paper we shall discuss mainly how delays and deviations may be minimised. Nevertheless, the procedures which result from this survey will lead to benefits for all and to a freer use of the terminal air space by other traffic.