From an Atlanta Journal Constitution article:
The U.S. Bureau of Transportation Statistics reported this week that Delta brought in $952 million in baggage fee revenue in 2010, the highest amount among all U.S. airlines. The AJC analyzed the numbers to scale baggage fee revenue based on the airline size as measured by number of passengers.
Delta carried the most passengers last year among U.S. airlines, with about 110.9 million boarding planes, according to Bureau of Transportation Statistics data
In surveys, passengers may say they can't stand bag fees, but they seem willing to pay them. As an employee of a company who made almost $1 Billion in revenue from them, I don't plan to argue against them (especially since that Billion funded my profit sharing check this year). In fact, the industry pulled in $5.7 Billion in fee revenue last year and while Southwest's 'no fee' marketing campaign may be noble, that's a huge pot of money to lose out on....Airtran pulled in more than $150 Million in bag fees and it would be interesting to be a fly on the wall of the meeting when SWA execs decide to end bag fees at Airtran to bring them in line and give up that cash.