Northwest Airlines is not going to create a low cost carrier within a carrier a la United and Delta (or like past failed operations at United, Continental, and USAirways). Smart move.
Northwest has, more than any of the other major carriers, transformed itself into a hybrif of low cost carrier and full service carrier. Their labor costs remain high. They’re a victim of their own relative success in that they haven’t had bankruptcy as a real stalking horse to reign in union contracts. But they have successfully controlled their other major expenses, and if they can bring their labor costs in line with their post-bankruptcy competitors they should survive without risky ventures that threaten to cannibalize their existing business.