Alaska already flies every one of these routes. Delta doesn't, and hasn't flown some of them in a very long time (mid 90's for Ixtapa/Zihuatenejo and Mazatlan).

We have (prior to H1N1) flown PVR and GDL from LAX, but that influenza virus has (temporarily, I hope) killed the business. One of the three Mexican majors, AVIACSA, shut down. If you go through Mexico City, you'll see a whole bunch of airplanes in AeroMexico and Mexicana colors parked. Delta has downgauged all the remaining Mexico flights (a lot fewer 757's, a lot more 737-700/800) and decreased frequency on many routes.

There was a story last week on Swine flu, and how as many as 50% of US residents could get it this winter. The flu decimated Asian travel to North America. If it returns this fall, there are going to be a whole bunch of empty flights going south of the border. My bet is that one of the other Mexican majors will fail or merge.

Delta was allowed to codeshare with AK as a result of the NWA merger. NWA used AK to feed their Gateway cities. With the drop off in Mexican tourism and the world recession, these routes were either going to be abandoned by Delta or codeshared. It does not make economic sense to compete against an incumbent carrier (AK) when you don't have a competitive advantage. The code share will experience its own difficulties, as AK is currently on the other side of the airport in a different terminal.

jmo, and I'm probably wrong.