Southwest Airlines on Sunday announced new service coming next spring for it and subsidiary AirTran Airways, with the big changes coming on AirTran routes to Mexico.

additionally:
Southwest announced new Houston nonstop service and AirTran will add nonstop service between Ft. Lauderdale/Hollywood and San Juan, Puerto Rico, as well as new Denver nonstop routes.

Southwest using AirTran to add Mexico routes - USATODAY.com

Southwest has announced plans for Mexico service, saying it will use its AirTran subsidiary to add the international routes from two Southwest cities.

In a move announced by Southwest, AirTran will add flights from San Antonio to Mexico City and Cancun beginning in May. From California's John Wayne Airport in Orange County, Southwest will begin service to Mexico City and Cabo San Lucas in June. All four proposed Mexico routes are pending approval from government regulators.

ALSO ONLINE: Snapshot of new Southwest/AirTran routes

Southwest also announced plans for AirTran to fly (starting May 24) from Fort Lauderdale to San Juan, Puerto Rico – a domestic route that does not need regulatory approval.

The Dallas Morning News notes the moves come "as new owner Southwest Airlines continues to revamp AirTran's schedule." Southwest (and subsidiary AirTran) also announced plans during the past three days to both add several new routes and to drop several cities from their combined route network.

As for the Mexico service, Southwest CFO Bob Jordan is quoted by Reuters as saying "I think this is the first of several announcements of new international service," though he didn't offer any other details.

SLIDESHOW: Southwest Airlines photos
SLIDESHOW: AirTran photos

And aside from the new Mexico cities, Orange County also will be a new destination for AirTran, which continues to fly separately from Southwest as Southwest continues to work toward receiving a joint operating certificate from the Federal Aviation Administration that would allow it to blend the two airlines' flight schedules.

The Fort Worth Star-Telegram notes Southwest already "has a large presence at Orange County and San Antonio, and Jordan said the carrier plans to have its code sharing arrangements with AirTran in place in the first half of next year. That would allow passengers to book tickets on Southwest and then connect to an international flight operated by AirTran."

"We do anticipate code-share support of these routes," Jordan is quoted as saying by the Morning News.

On the Mexico service, Dow Jones Newswires writes:

Mexico is one of the largest markets where the U.S. lacks an open-skies treaty that allows unlimited flying between countries. However, Mexico has been relaxed about increased capacity since the collapse last year of Mexicana Airlines.

I've been out of the loop for a while, but there used to be a requirement on passenger manifests of seat assignments on international flights. I realize this is still under FLs ops. specs. but has this requirement changed?

NK missed the boat when they were there......

WRT San Antonio and Mexico flights:

United tried and pulled out.
Continental tried and pulled out.

We'll see if Southwest/AAI will try it and then pull out.

How many peso's does it cost to get an early check in?

Unfortunately, Dallas and Houston can't be used for international so it has to be SAT. It will be interesting.

I thought the same thing when I read this. SAT is not a hub regardless of how many airlines try and make it one. (Expressjet branded is another)

Expressjet Branded didn't make it anywhere.