I recommend Boeing because the 737 family runs for almost the entire game length and has lots of aircraft to choose from. The 767 or 747 family are good long range family's that once they start you can use them for the rest of the game.
I am aiming for a airline that offers great service for a reasonable price so I thought that those kinds of alliances would be the same. On the note of Alaska. I have closed my hub in STL and have shortened my terminal so that I am barely doing any flights out of there. Just like Alaska Airlines I have an all boeing fleet, I have just expanded the route network and fleet size to reflect my hopes of what I hope Alaska Airlines will eventually become.