It aimed to compete with Southwest and other low-cost competitors but has been a disappointment.

Nothing you can do with Southwest," said the driver, "but get across it.

David Neeleman worked with Southwest for a short period.

Even if their combination would create a bigger airline, "how can you compete with Southwest?"

Nor are the improvements necessarily related to the negotiations with Southwest.

On routes where United's new service will compete directly with Southwest, fares may drop further.

It would be far more costly not to compete with Southwest and abandon the customers we've worked so hard to keep.

Braniff, which competed directly with Southwest in Texas, later failed.

But what convinced him to stay with Southwest was the service.

One such is American, which competes with Southwest on 70 percent of its routes.