"Someone misses their flight in LGA/JFK, well now they are probably going through ATL and the stacks of HKs start adding up." <--- THIS so true, will drive you nuts some days - or just try and go as early as possible to avoid some of the HK factor on DL. AT/SWA is indeed a good backup in lieu of riding on DL - 3/4 of the time seats in First Class are open on AT.