AIR ROUTES

A natural limit is set to the length of great land and sea routes by the extent of the continent and oceans. It would appear at first that there is no such natural limit to air routes. In the early days of long-distance flying, however, the relatively short range of aircraft led to air routes being planned to avoid:-
(a) Large stretches of ocean. Air routes took the shortest sea crossings, as far as possible keeping to the land and to chains of islands.
(b) High mountain areas where cloud, poor visibility, or ice formation on aircraft, may make flying dangerous in bad weather.
(C) Extensive forest areas where landing is obviously difficult.
Thus those very barriers that impede Man's progress on land were effective in limiting his choice of air routes . Owing to the great improvement in aircraft performance and reliability, there are now no areas where the choice of a route is limited by physical features.
The main factors influencing the selection of routes to-day are ground facilities and sufficient traffic for economic working.
The operation of mordern aircraft demands much assistance from the ground in the way of air traffic control radio aids to navigation, meteorological services, suitable runway and airports, passengers-handing and customs facilities and proper maintenance. Because these services are naturally more readily obtainable in the more densely populated areas, and because these same areas are those in which the demand for air services is greatest, the main air routes still often continue to avoid areas of scanty population.