The current plan of keeping T2, expanding T4, tearing down T3 and building the longest bridge in the universe will be adequate to meet DL's needs, but not ideal. Getting from T2 to T4 when its all said and done will result in, I think literally, the longest walk in the world at any airport within a given airline's terminal system from furthest gate to furthest gate.

T5 is a much better match with T4. Plus the roof on top already has the perfect space for the widget of imperial domination.

Also I don't buy the talking point about how the vacant T3 space will be useful as some parallel universe platform 9 and 3/4 to stash irop aircraft or do donuts in 777's or whatever it is they were trying to sell when they came up with that nonsense. I see something being built there, just not now and maybe not even by DL.

There's a lot of speculation about T6, and as CR mentioned above, some think it will become a combined JB terminal. That is certainlly a very viable possibility, but I really don't buy any claims that JB (or any airline for that matter) "owns" any terminal, especially one they aren't using. I suspect they probably have some first right of refusal to some extent, but even that would have to be the sexiest offer to the bureaucrats. I very much doubt they have a blank check on it especially if someone else (SWA?) makes a move on it. To really do anything grand with it will require epic capex, although you could throw a hundred mil or so of lipstick on it (nothing gets done cheap in NYC) and it would be OK. But I'd love to see the fire marshall sign off on T6 filled with foreign widebody pax. Remember, the same talking heads that say JB "owns" T6 and "will" make an international powerhouse terminal out of it or whatever are the same ones that have been saying for many years that T5 couldn't handel the weight of widebodies. LOLZ!

Also JB has been getting pretty much a free pass with their little code share frenzy. I suspect those salad days are coming to an end. Once DL gets a massive LGA domestic hub in place and is running a better JFK ops with at least a partial terminal solution and UA gets their merger sewed up, and especially when AA/US tie the knot, the competition will really kick into gear. I'd expect a lot of the relatively modest amount of marketshare all the legacys havebeen losing to JB's little foreign code share with any flag carrier on earth to suddenly become significantly less lucrative. The biggest one, LH, will be able to tap into a much bigger NYC market with UCAL at EWR than what JB can offer, and with first class and higher frequency to most markets anyway. Most of the others will be crushed by VASTLY superior connecitvity on either or both ends.

So no, DL doesn't "need" T5 (although it would be nice to have and building a bridge between 5 and 4 wouldn't be that big of a deal), and IMHO will probably not end up in it. I'd give it a 33% chance of happening, however JB's future with AA/US and/or SWA plays out.