Eero Saarinen’s masterpiece, the long-empty TWA terminal at JFK Airport, “is making a halfway comeback. The Port Authority has begun to restore it, but the work won’t be finished for months, and it remains unclear whether the building has a destiny as a food court or just a white elephant. Meanwhile JetBlue has transformed it into a neat little accessory for its new $743 million Terminal 5, designed by Gensler.”