Welcome to the "steaming pile of failure." New Orleans? How about Los Angeles? Would you believe EDGE in LAX? Fortunately for me, I had my Verizon MiFi for backup. Needless to say, Verizon had 3G in the same spot where AT&T did not. But an international airport in a major city? Give me a break.
Remember Cingular? No 3G. They got what little 3G coverage they have when they merged with AT&T Wireless. The merged companies retained the AT&T name but it is the old Cingular, no 3G, management that runs things.
Not to worry, they are promising 3G in Vermont, for all the cows that use iPhones. On New Years day I drove the length of the state on I91. I saw 3G for a mile or two in White River Junction (those who know the road understqnd that the 3G cell is really in New Hampshire).
The end of the month I will go to SF. Last year there was not enough data, EDGE or 3G, to download a big page. We will see if they have gotten better in a year. In April I will go to New Orleans, mostly west. I will give a report.