AC

Almost a year after Delta Air Lines announced it would buy Northwest Airlines and become the world's biggest carrier, fliers will soon start seeing the first outward signs that the two carriers are becoming one. By the end of March, all the "Northwest" signs at Northwest's longtime hubs in Minneapolis, Detroit and Memphis will be replaced by Delta DAL signs and Delta's bright red triangular logo. And pilots, flight attendants, ticket agents and gate agents of both airlines will be outfitted alike in Delta uniforms. But for two major airlines that have operated separately for decades with different route structures, corporate cultures and passenger policies, the hard stuff — such as merging two giant and complex reservations systems — will not happen until next year, Delta executives say. "When airlines merge, they have to think about legal issues, communications, maintenance, real estate and so on," says consultant Jerry Glass, the former human resources chief for US Airways,...