In all areas of marketing, links must be made between the customer and the product. These links are known as distribution channels. Airlines use a variety of these channels. All of them are giving rise to particularly intense debate at the present time, because the channels each result in different costs, and because they vary in the extent to which they allow airlines to exercise proper and necessary control of the market. It is also an area where radical and controversial change is occurring, as carriers become increasingly adept at exploiting the potential open to them from on-line distribution.