Here's a bit more from the AP:
Southwest Airlines to begin service in Philadelphia
Associated Press
PHILADELPHIA - City officials were to announce Tuesday that Southwest
Airlines, the largest discount air carrier in the nation, plans to
begin service in Philadelphia starting in May.
Southwest chairman Herb Kelleher is scheduled to announce the
company's plans on Tuesday at a news conference at the airport, The
Philadelphia Inquirer reported. The airline declined to comment on
the deal.
City Aviation Director Charles J. Isdell, 53, said the entry of the
Dallas-based airline to Philadelphia International Airport was the
most dramatic change to the airport "in my lifetime."
Southwest plans to initially offer about 40 flights a day and occupy
four gates at the end of a terminal previously leased to American
Airlines, which gave up the rights to the gates last year.
Airport officials said the airline's routes to and from Philadelphia
would likely be disclosed in December.
The addition of Southwest, the nation's second-largest airline, could
negatively affect business for US Airways, a major city employer that
provides service to 58 percent of the city's airport traffic, The
Inquirer said.
"We are always concerned about US Airways in terms of their
viability," Isdell said. But, he added, "even if we did not want
(Southwest) to come in, to protect US airways, we have no legal right
to stop them."
Wow! What a stunning development; a very aggressive move. I guess SWA doesn't see US Airways as having enough financial muscle anymore to put up much of a defense. SWA clearly wants to be a major player on the east coast, and instead of nibbling around the edges of US Airways' cities, they've decided the time is right to go for the jugular.