I got sale emails from Southwest and Jetblue today so you might want to recheck.
It appears there will be no more Airtran out of Buffalo. On one hand I am disappointed that there is less competition, on the other hand I really didn't like Airtran and avoided them when I could.
Take a look at United and Delta as well. If you are flying out of Buffalo they won't be non-stops, but it might be worth the trade off if they are way cheaper than the others.