spirit's website suggests arriving 3 hours prior to departure time...this adds six hours to a 2 plus hour flight twice...add travel time to airport itself...we fly spirit exclusively for wdw, but this october trip we will rent minivan at ac airport for $400 and drive (unlimited miles w/ hertz via orbitz)...spirit is no-frills, no nonsense, herd you on the plane, you're up, get a soda & you're on the ground...but beware, the tix are non-refundable, you can alter names & dates for a fee, but it is definitely not a flexible carrier...we've only experienced one delayed flight in like 8 years of flying with them, and the early morning flights have less delays; they are adding more flights out of ac in november...i hear usair flights are cheap out of phila, but we hate dealing with philly airport hassles & parking...tough call, i don't envy you