I think that if Frontier had launched a replacement route, it would be short-lived (September and October months only) as it probably had in mind at some point to discontinue the ILG based plane setup temporarily or permanently later in October.

If ILG had kept the plane, I'd think RDU would make some sense. I know a few in South Jersey, Philly that looked at the TTN-RDU flight but were uninterested in the 6:25am departure.

However, those flights are doing very well.

Some of those very early morning flights out of TTN, I believe it's RDU and ATL currently are flown more than 4x weekly, might be filled with Central NJ locals (including business pax) that might be flying out for work and avoiding the hassle of going up to EWR atleast first thing in the morning.

The ILG-ATL flights are still very cheap, and much cheaper than IAD-ATL and TTN-ATL. Is there any word if these will return next Spring? With Frontier opening in PHX on routes like PHX-IAH and PHX-SLC and willing to compete head on with US and Southwest, I think it's fearless now. It might just throw a frequency on ATL-BWI and ATL-PHL and get better yields with more sales going out fast and then higher fares, even though it doesn't generally service those airports. I could see Spirit considering atleast ATL-BWI as well too.