Hi. I don't believe that AA will dramatically increase their operations out of JFK. The only reason they are completing construction on the new terminal is because they were beyond the point of no return post-9/11, and it wouldn't make economic sense for them to halt or even postpone the project. AA has never had hub operations, don't have hub operations and probably never will have hub operations at JFK. Right now they fly to LHR, CDG, LAX, SFO, RDU, DFW, LGB, ONT, MCO, MIA, NRT, BOS, DCA and I'm sure there are a few others. But it's not a huge selection of destinations and AA has never stated any intention to increase the scope of their operations here. Besides, they have three hubs already -- DFW, ORD and STL. JFK would make a great gateway city for them and I think that's what they intend to do. I could be wrong though and I hope I am -- I would LOVE to have a major have hub operations out of JFK.
With the exception of LHR, Delta operates the old TWA routes to Europe. They have a few domestic flights to ATL, LAX, SFO, MIA, MCO, FLL and perhaps a few others, plus a flight to YYZ (which is essentially a feeder flight for SA's flight to JHB). No major hub operations from them. I believe they do operate the most of flights out of here though. Delta just has gateway city operations at JFK and their present facilities suit them fine. The terminal upgrade was for cosmetics only. Why they're continuing with the terminal construction at Boston is beyond me, especially since they axed the flight to LGW.
JetBlue, on the other hand, is dramatically increasing their presence here. They are the biggest domestic carrier at JFK and will soon be number one in movements too. I don't see too, too aggressive expansion, maybe adding some more frequencies to routes they presently serve. Prior to 9/11, JetBlue wanted to increase their operations by 300 flights within the next year. I don't think they'll do that anytime, especially with AA lurking around. AA has been aggressively targeting JetBlue routes, trying to run them out of business. I hope JetBlue's management is smart enough to realize this and hold off on their aggressive expansion for now.
Even so, I don't think JFK will need new runways soon. What they have now is more than enough for a large scale growth in airline operations. I cannot emphasize enough how UNDER capacity JFK is now -- even before 9/11. But things are somewhat back to normal now, which still means there's always room for more.