What is an airline hub?

The model is called hub and spoke, and the arithmetic behind it is the reason nearly every large airline uses one. Connecting ten cities directly to each other takes forty five routes. Connecting the same ten through a single hub takes ten. The passenger pays for that efficiency with a connection; the airline pays for it with a schedule built around banks of arrivals and departures a few hours apart.

In the United States the major hubs are easy to list by carrier. American concentrates at Dallas Fort Worth, Charlotte, Miami and Philadelphia. Delta builds around Atlanta, Detroit, Minneapolis and Salt Lake City. United uses Newark, Chicago, Houston, Denver and San Francisco. Where you live relative to those airports shapes which airline is realistically yours.

Hubs matter to premium travelers for a reason that has nothing to do with convenience. An airline defends its hub, which means fares out of it are often higher rather than lower, since competitors have thinner service there. The cheapest long haul business class fare from a hub city is frequently on a rival carrier connecting through a different hub entirely.

The same logic applies at the other end. Flying into a European or Gulf hub gives you a wide onward network and usually better premium inventory, because the airline is filling an aircraft that continues past your destination. That is why routings through Doha, Istanbul, Frankfurt or Amsterdam so often undercut a thin nonstop, and why the choice of hub is worth as much attention as the choice of airline.