I was looking at Frontier's winter schedule, and noticed that really the experimental flying makes a small percentage of Frontier's overall network.

The largest part of Frontier's network is DEN flying. I think AA is not very strong or in position to fare match a lot of routes between the Midwest and the West, like it can everything east of ORD using ORD, PHL or DCA-Florida. The other major % of Frontier's network is LAS and MCO flying. Many of those routes don't directly compete against AA.

To me, some route question marks are PHL-MIA and IAD-MCO. I noticed that IAD-ATL is being cut on March 16 which might indicate even further weakness on the IAD side. Southwest is operating IAD-ATL this winter season. This will leave F9 with one IAD flight, although it has three DCA-DEN flights with connections to the West.

Both JetBlue and AA have been pretty fare aggressive on DCA-MCO (and other DCA-Florida routes), that I don't know if F9's single IAD-MCO which is left has a chance.

Also, since IAD is a more expensive to operate and less liked airport between DCA and IAD, so F9 is even more disadvantaged. The IAD demographic doesn't really fit in with the F9 demographic, unless some pax are just choosing IAD flights over DCA ones for parking convenience at IAD if they live very close to IAD.

At PHL, the PHL-MIA flight might not do as well with AA and B6 (and WN) all competing for the PHL-So. Florida market this winter. During the winter, this is going to be driven more by PHL point of sale, rather than Miami-Dade Co. point of sale where operating from MIA was supposed to target. MIA has higher costs than FLL. I could see that route going "seasonal" (euphemistically for suspended) with an iffy chance of returning. Unlike Orlando which does well as a year-round market, South Florida demand tends to be more seasonal.

AA has been aggressive on ORD-ATL and PHL-ATL which might be why those ATL routes were suspended from F9. AA doesn't honor a 24-hour cancellation at no charge policy (unlike UA and other carriers) if one decides to cancel for a flight that is booked within 7 days. Southwest tends to fare very high for flights that are booked within 10 days - which provides opportunity for the ULCCs, but AA's faring practices make it more difficult. It's fare visibility (through third party sites) and allowing pax to select their seats also makes it attractive for those that might have gone with F9 or NK but not WN.

I wouldn't be surprised if PHL/TTN, CLE, CVG, IAD, etc are smaller spoke regions going forward. Even ATL and MIA. F9's decision to base a crew in MCO lends to me believe there will be more MCO flights, probably to existing F9 cities that have DEN service. It's LAS build up might also follow a similar pattern. F9 might still do well in ORD especially on ORD-West routes where AA doesn't dominate. AA has it's roles for connections and higher yielding O&D for longer routes, that it might not be able to fare match too much. The ORD originating market is still pretty big that there might be a lot of customers willing to put with a low end product. I can't say for certain because NK is there too, and fares on the better carriers have come down since on several of those routes.