More power to them! I'll sign the petition for them to secede -- especially if Texas is included with them. As far as their economy goes, I'm sure they'll do very well. Of course, Atlanta won't be a main airline hub for the U.S. anymore, that will shift to some other city.
Lets see, Florida, Georgia, Alabama, Mississippi, Louisiana, Texas, Arkansas, Tennessee, South Carolina, North Carolina, Virginia -- those are the eleven right there. So maybe St. Louis would become the new southern airline hub. Or Oklahoma City, or Lincoln, or Cincinnati, or Louisville or Baltimore. Boy, this will be great news for some remaining U.S. city. They'll be fighting over it! Great news for California, too. New Yorkers won't need a passport to go south for vacation. Of course, the federal government will have to move the southern border fence to surround Texas on three sides to the north to keep the Texans out, but, hey!