Hi

Need some advise on choosing between NWA and AA coming year. This year I spent almost 60K on airline tickets, all within continental US. Ended up with 58K flight miles on AA, 62K flight miles on NW (some, I flew continental but enrolled in worldperks) and 35K miles on UA, Amer. West, Midwest Airlines. Home airport is DCA/IAD. Work takes me to MSP, DFW, IAH, DEN, COS, STL, MCI, DSM, SJC/OAK/SFO. Usually buy the cheapest ticket/convinient times/less connections available through orbitz. I like NW because of the free upgrades unlike AA where I have to either buy an upgrade or use those 500 mile stickers.

My goal this year would be to stick with one airline and attain max level. Which airline would you recommend?