When US and AA combine, neither JFK nor PHL will be going anywhere.
Not even Doug Parker is stupid enough to abandon AA's JFK network, even though he was dumb enough to trade most of US' LGA slots to DL for some magic beans (a few slots at DCA). NYC is the nation's largest air travel market and AA (on its own) or US-AA merged will continue to serve JFK (and LGA) with lots of service.
PHL doesn't have the O&D that NYC possesses, but PHL will continue to have nonstop flights to places beyond the other hubs - in other words, PHL will not become a mere spoke.
I didn't say either would go. I said if any flights were to be shifted, they would be shifted from JFK to PHL. If US AAirways decided to start up new long haul flying, I'd wager it'd be from Philadelphia and not JFK. American can't even make Frankfurt-New york City work... nor Amsterdam nor Lisbon nor Milan nor Munich nor Athens nor Dublin nor Tel Aviv.... (I believe).
And while PHL will never have the O&D of NYC, American at JFK will never ever come close to the size of US Airways at Philadelphia. Also, NYC belong to Delta & United and JetBlue is the same size as AMR in NYC. There is no place for American in NYC anymore just as there isn't at Boston.
JFK will be put on the back burner to PHL. Thats just my thinking.
US has 440 daily flights out of PHL (630 in Charlotte, 200 DCA, 270 PHX). AMR will never have 440 daily flights out of JFK. And the competition is huge in NYC (And AMR has MISSED THE BOAT in NYC. Its done. This is 2012 where Delta/United dominate NYC along with JetBlue and foriegn carriers).
If you picked up Dallas and put it in Philadelphia's place, you wouldn't pull resources from Dallas to give to the hopeless 4 corner strategy that is JFK. Let JFK Have the big O&D cities such as Paris, London, Madrid, Frankfurt (bad example), etc. and let "Dallas" (Philadelphia) have routes that need more connections (Athens, Brussels, Milan, Lisbon).
If I'm not Mistaken American Airlines actually does fly Dallas to Frankfurt but doesn't fly JFK to Frankfurt... correct? Despite this massive O&D we hear about...