All the major airlines cut deeply into nonstop service to leisure destinations from airports where they do not maintain hubs.
American's only other path to profitable growth is adding "point-to-point" flights between cities where it doesn't maintain hubs.
Some hubs (strong hubs) maintain the hub status in all the tissues where they are expressed, whereas others (weak hubs), in spite of their ubiquitous expression, are hubs only in some tissues.
The Lib Dems will support a consultation by Justine Greening, the transport secretary, on how to maintain a hub, but they will oppose any new airport.
As examples, shipping lines currently maintain multiple hub ports simultaneously to expand market coverage, thus incorporating the market-oriented approach.
Which is precisely where these airlines maintain their hubs: Doha, Abu Dhabi and Dubai.
He maintains the hub of his business in London and has opened branches around the world from New Delhi to Sydney.
Indeed, brokers who find tenants for distribution centers, particularly places like Memphis, where Federal Express maintains a hub, and Columbus, Ohio, which is less than a day's truck ride from many other urban areas, say they are getting top dollar for their properties.
HSBC's group chairman, Douglas Flint, said: "As we evaluated jurisdictions against the specified criteria, it became clear that the combination of our strategic focus on Asia and maintaining our hub in one of the world's leading international financial centres, London, was not only compatible, but offered the best outcome for our customers and shareholders.
Some hubs (strong hubs) maintain a high ratio of the active connections among all the possible connections pertaining to them in the reference network (i.e. active ratio), and therefore keep their hub status in all the tissues where they are expressed (Fig. 2a and b).
