Major Airlines Offering New Discounts : Travel: The price reductions are in response to fare cuts made by Northwest Airlines over the weekend.

Major airlines Monday began a new round of discounted air fares--matching lower fares initiated by Northwest Airlines over the weekend--in an effort to boost still-sluggish summer bookings.

The latest fare cuts come on the heels of the industry’s recent spring discount promotions, which analysts said were only moderately successful in increasing advanced bookings for the summer. The four-week spring promotions, which ended April 9, were initiated at the end of the Persian Gulf crisis--a period when air travel dropped to dismal lows.

“My sense is that advance bookings are still mediocre,” said Paul Karos, an analyst with First Boston Corp. “You don’t usually discount going into the summer period. That is when you are usually guaranteed that people are going to fly. The economy is recovering, but it is a slow recovery.”

The Air Transport Assn., the industry trade group, said recently that April traffic was off 4.2% compared to the same period a year ago.

“This is part of a ratcheting downward of some of the fares that had been raised because of the increase in fuel prices in the winter,” said Timothy Pettee, airline analyst with Alliance Capital Group. Said Robert Decker, airline analyst with Duff & Phelps in Chicago: “The airlines want to get more people on the planes and are willing to discount to do it.”

Eagan, Minn.-based Northwest on Sunday cut its fares 60% for children traveling with an adult and 17% for adults on trips within the continental United States. But tickets must be purchased seven days in advance and before May 31 for travel through Sept. 8.

Dallas-based American Airlines on Monday lopped 15% to 20% off its current discounted fares in response to the Northwest cuts. It applied the new fares to all its routes, not just those on which it competes with Northwest. American’s tickets must be purchased by June 1 for travel through Sept. 30. The carrier said the fares are being offered in more than 14,000 domestic markets, with the percentage discount varying by market.

American said its current lowest fare between Los Angeles and New York is for a 14-day advance purchase ticket. The new discounts will reduce that fare to $358 from $385 round-trip during hours when travel is slowest. The peak-hours fare on that route will be reduced to $398 from $425, American said.

Chicago-based United Airlines said it would match the Northwest and American discounts. Atlanta-based Delta Air Lines, Continental Airlines in Houston and New York-based Pan American World Airways said they would match the Northwest discounts.

“The domestic traffic is the only one that is behind” booking expectations, a Pan Am spokesman said. “Our Latin American and Transatlantic bookings are ahead of plans.”

Meanwhile, Dallas-based Southwest Airlines on Monday extended its promotion allowing anyone 17 years old and under to fly free when accompanied by an adult paying full fare.

The original promotion allowed tickets to be purchased by May 22, 1991, for travel through Aug. 12, 1991. Under the new rules, Southwest said, customers have until June 4 to buy the tickets and can fly through Sept. 4. Southwest said tickets purchased under its promotion are refundable and are good for travel seven days a week.