We just used Airtran in early January (NYD and return 1/8) and had great, on-time flights with them from ABE. We usually make a 2 hr trek to PHL and fly SWA, however, the hour drive and smaller airport were very nice and I'm quite sure we'll do again. Currently, AT only has flights on Mon, Wed, Fri, Sat and Sun and only one of each of those days. However, upon checking the schedule for the summer months, it appears they are adding more flights to/from ABE and then in September, back to one flight. The summer schedule shows a few connecting flights and I believe, one nonstop flight......if I recall correctly, maybe 4 flights per day?