Northwest Airlines will follow a recent industry...

Northwest Airlines will follow a recent industry trend by raising prices and imposing longer advance-purchase requirements on discount fares, the carrier said. The move closely parallels similar plans announced earlier by United Airlines, American Airlines and Delta Air Lines. All the fare increases would be effective Sept. 8. Under Northwest’s proposal, the lowest “MaxSaver� discount fares would require a 14-day advance purchase. The price of those non-refundable tickets will increase by $10 each way. A seven-day advance purchase fare will be 50% refundable and will cost $40 more each way than the current non-refundable fares. The main question is still whether Texas Air Corp.--the industry’s price leader with about 20% of the U.S. market--will follow suit. A similar increase by Texas Air, which owns Continental Airlines and Eastern Airlines, would probably be needed to make the plans stick, analysts say.