Although America has dozens of regional and local airlines, only seven have a nationwide presence. Delta and Northwest have announced a merger, and United is actively courting another airline, recently rumored to be US Airways. If these proposed mergers were approved, would it lead to a substantial lessening of competition in commercial aviation?

The answer almost certainly is: “No.”

Even with five nationwide carriers, the opportunities to raise airfares would be illusory. The mergers are not motivated by the idea of raising prices, but of reducing cost structures.

Consider the networks or airport hubs serving scores of cities: Delta currently has hub operations in Atlanta, Cincinnati, Salt Lake City, Los Angeles, and JFK. Northwest has hubs in Minneapolis, Detroit, Memphis, Tokyo, and Amsterdam. If all existing hubs and routes were to be preserved, there would be little point of a merger. No rational airline would construct a network with eight hubs in America.

The exact choice and timing of reducing operations at a hub or along certain routes depends on several factors, including contracts for facilities, personnel, and services at individual airports. Those contracts would not likely immediately dissolve if a merger were approved. On the other hand, those contracts are not permanent, either.

Similarly, US Airways has hubs in Philadelphia, Charlotte, Phoenix, and Las Vegas. United has hubs in Washington, Chicago, Denver, and Los Angeles. Should a merger be announced and approved, it is difficult to imagine that the combined airline would keep eight hubs.

The mergers cannot happen soon enough for these airlines, which, along with most other major airlines, are losing substantial sums of money. A few smaller carriers are in bankruptcy. Fuel costs are certainly partly to blame, but many airlines were losing money even when fuel prices were half of today’s rates. Combining two major airlines would not lower the cost of jet fuel, but it might just lead to a more efficient route map with fewer hubs and fewer planes, and fewer empty or low-priced seats serving roughly the same number of passengers. If such efficiencies were not possible, the mergers would be pointless.

Any merger, of course, must first be approved by the Department of Justice, and that approval is far from certain. Members of Congress have voiced concern, and so too have many local government officials. The economic concern partly will reflect competition for airline traffic between hubs of the two carriers, such as between Minneapolis and Atlanta.

But much of the political concern reflects the competitive choices available in mid-size and small markets such as Albany, Buffalo, and Rochester. Today, a passenger seeking to fly to Baton Rouge, La., or scores of other towns across America from upstate New York must change planes at a larger hub. Delta and Northwest both offer those services today. So does United and other carriers. Tomorrow, one or more of the current set of airlines and hubs may not be available.

As long as new businesses can enter the airline market, however, it will remain competitive regardless of any series of airline mergers. If a combined Delta and Northwest were hypothetically to close hubs in Cincinnati and Memphis, new or existing carriers would take many if not all of the vacated airport facilities and landing slots and offer competing services.

Unlike military generals, old airlines do not simply fade away. Some die, but most are purchased by larger and more energetic rivals. Delta, Northwest, United, and US Air grew as much by corporate acquisition as by internal expansion. Over the past three decades, dozens of airlines have been bought and sold.

The result has not been an oligopoly of a few carriers, but rather ever more competition from new entrants. Practically every airport sports airplanes with logos of airlines that did not exist 10 years ago. Some of these new airlines will survive; some will not. All, though, will help discipline an airline pricing structure where profits are more often a matter of faith in the future than the reality of today.

Some observers see the merger of Delta and Northwestern, along with rumored mergers among other major airlines, as the conspiratorial end of competition in the American airline industry. The exact opposite is almost certainly the case.

A former FCC commissioner, Mr. Furchtgott-Roth is president of Furchtgott-Roth Economic Enterprises. He can be reached at hfr@furchtgott-roth.com.