Following a similar agreement with Canadian carrier WestJet, Southwest Airlines will codeshare with Mexican airline Volaris.

Southwest through its web site will sell existing domestic Volaris service and future transborder flights starting in spring 2009, followed by connecting codeshare flights.

An Airbus A320 and A319 operator, Volaris serves 39 routes in 23 cities in Mexico. The airline aims to launch international operations in 2010 with service to the United States, Central America and the Caribbean.

Also in early 2010, Volaris and Southwest plan to announce codeshare flight schedules and additional features regarding their partnership, which will require regulatory approval for certain aspects.

The deal between the low-cost carriers will eventually allow each airline to check both passengers and baggage to a passenger's final destination.

Other areas of possible cooperation include frequent flier options, ground handling and cargo.

As ATI previously reported, a Mexican codeshare partner appeals to Southwest for a variety of reasons.

Roughly 17 million passengers travel between the USA and Mexico annually, of which 75% to 80% of those passengers travel through cities where Southwest already has a presence, carrier executive vice president strategy and planning Bob Jordan said during the Southwest's media day on 1 October.

"We don't have to modify our network much," he says.

The carrier is indicating more codeshares are in development. "We are continuing to look for ways to expand our network through international codeshare partnerships, and we are excited to team up with Volaris to offer our customers access to attractive Mexican destinations," Jordan says in a statement.

Source: Air Transport Intelligence news