Southwest's new schedule is out, and I found some interesting schedule changes:

IAD:
IAD-MDW at 2x daily (Frontier announced IAD-ORD)
IAD-DEN at 3x daily (typically Southwest has run it as 2x daily)
IAD-LAS added (Frontier announced this route as well). Both Southwest and Frontier might pressure UA out.
IAD-SAN added (Southwest is largest carrier in SAN)

PHL:
PHL-ATL drops down to 3x daily (maybe good for ILG-ATL and TTN-ATL)
PHL-FLL returns 2x daily
PHL-PBI returns 1x daily
PHL-MCO at 5x daily
PHL-TPA at 2x daily
PHL-RSW (missing in action)

PHL-ATL drops to 3x daily and is priced rather high, with connection feed in mind and maybe Southwest pricing high realizing US and Delta will just match whatever Southwest prices.

On Frontier's angle, it's good that TTN-ATL and ILG-ATL can be still attractive for low fares rather exclusively, just to/from ATL.

For Florida, Southwest has dedicated interest in keeping FLL in the winter time as well as PBI, however. Nonstop RSW is missing from Southwest's schedule from PHL.

I checked the CLE market, and couldn't see any noticeable changes.

I also noticed some lingering routes that it has like BWI-GSP at just 1x daily and in the evening, not timed for business traffic. If US starts price-matching Frontier on IAD-CLT, would Frontier consider GSP in lieu of CLT, and IAD-GSP? TTN-GSP? It'd get F9 into So. Carolina and maybe GSP which is a weak WN station.