It looks like Southwest is going after US AIRWAYS by taking on more gates at Philadelphia International Airport.

Southwest operates from six gates at the Philadelphia airport now. By early January, the airline plans to take over leases on two gates used by UAL Corp.’s United Airlines, said Steve Sisneros, Southwest’s manager of properties. By spring, Southwest will get four gates now used by Delta Air Lines Inc.

Southwest’s expansion could further pressure US Airways to cut prices. In 2004, when Southwest invaded US Airways’ Philadelphia turf, average one-way fares here dropped 26%.

Southwest serves 61 cities nationwide, and it recently announced plans to start flying from Denver.

US Airways spokesman Philip Gee told The Philadelphia Inquirer for a story in Thursday editions that the airline wasn’t fazed by Southwest’s expansion plans. He said America West Airlines, which acquired US Airways out of bankruptcy court, has competed for years with Southwest in Las Vegas and Phoenix, where both airlines have hubs. US Airways and America West are merging their operations under the deal, which was completed in September. via USA Today