Originally Posted by GW McLintock

T4 is Terminal 4; the flight status engine is prepopulated to say Terminal 5, so if it says T4 then it will go to a gate in Terminal 4. Honestly it's a toss-up, at least back in the day when I flew internationally a lot and mostly redeyes from points south, unless it was mega-early (like before 0415 or earlier) then they'd often just wait at a T5 gate and hold people on the plane until CBP opened at 0500. Sucks but for JetBlue at least it's faster than going to T4, getting a tug over there and bringing it back to T5. I'd suggest checking one last time before you start heading towards the airport (or better yet, pick them up at Federal Circle).

-J.