For the major airlines, the logic of the cuts was dictated by the hub-and-spoke networks they have established in the two decades since the industry was deregulated in the late 1970's.

Dr. Stevens puts it just as opaquely: "We have a hub-and-spoke network.

But American says staying with its hub-and-spoke network is the wisest course.

The Cargo division of the airline uses a similar hub-and-spoke network of operations.

Both the reservation systems and the hub-and-spoke networks pioneered by American carriers have been copied by airlines elsewhere.

Although American has said it is sticking with its hub-and-spoke network, United Airlines and Delta Air Lines are following Continental's lead.

The airlines agreed to attempt as many point-to-point transit flights as possible, although they would still have to operate some flights via a hub-and-spoke network.

British Airways is interested in developing Brussels airport as the center of a hub-and-spoke network.

Using this initial hub-and-spoke network, tunnels between spokes can be dynamically built on demand (dynamic-mesh) without additional configuration on the hubs or spokes.

The bus network operates predominately in a hub-and-spoke network starting with the downtown Portland transit mall, and includes outlying transit centers in Portland's suburbs.