During the past two years the commercial airline operators and the travelling public alike have been forced to acknowledge the rapid increase in airport congestion. This problem is most marked in the North Eastern area of America at the present time but a similar situation will develop fairly soon at major airports in Europe. Even with the introduction of the airbus to scheduled services, the number of aircraft movements at conventional airports, within a given time period, will reach a maximum safe level. The restrictions are imposed partly by the large number of aircraft operations on each runway, and partly by Air Traffic Control safety limits.