In the future flashes Jack was desparate to get back to the island and realised it was a mistake getting rescued.
Ben had told him "what have you to go back to your dad is dead your wife has left you"
Jack talked about a golden airline ticket presumably from oceanic for the now celebity survivors ,which gave unlimited free air travel.
He longed for the plane to crash and take him back to the island.
So im guessing season 4 will concentrate on those who were left behind on the island-Locke and the others.