Careful with Frontier. Cheap airfare, but fee for carry on bag, fee for seat assignment, fee for snack and soft drink. Also, most flights out of PHL are early morning, so its OK if your schedule allows for it. On a more personal level, on American (US Airway) or Southwest, I was treated as a paying customer, not as a head of sheep. I don't think the few dollars saved is going to get me to use Frontier in the future.