It should be interesting how AA will fare match F9 with so many markets out of PHL and less than daily. It will certainly be keeping AA on it's toes, also with the NK markets on it's plate. However, I wonder if a route like PHL-MCI at 3x weekly for half of the year will gain enough buzz. Certainly there might be people who were going between these markets on leisure (maybe visiting family), but Philly or Kansas City isn't all that destinational. Also given that it's over 600 miles, it will have to compete against connection flights such as DL selling a connection through JFK, ATL, DTW or UA or WN selling one through Chicago.

One route that I'd love to see Spirit or Frontier take on is PHX-LAS. For such a short route, Southwest charges near $100 fares for their lowest advance purchase. I'd guess Spirit or Frontier could offer below $50 fares as a baseline.