How do you figure Delta beating out AA??
Well:
Sky Pesos
Difficulty finding award space
Horrid pricing of oneway awards
(Their Mile program is
terrible. Might be the worst of any major airline in the world. AA mile program is effing amazing - esp if you can work with an Explorer Award)
Lackluster lounges esp at major hubs
Gift cards that expire the soonest of any major airline
You can't use their gift cards at delta.com
You can't buy gift cards online
Higher hub premiums than I've seen with other airlines
Booking skyteam partners on delta.com is more difficult than united or AA esp for more complex itineraries
Perhaps the most illiterate phone agents I have ever encountered
Behind the times Business/First class offerings
General crappy customer service experiences
Just off the top of my head
