Major Airlines Match 40% Cut; Increase Announced

Major airlines are cutting air fares up to 40% for trips through mid-January, but passengers must make their reservations by Friday and popular travel dates around the holidays are not included.

At the same time, many airlines are raising long-distance round-trip fares $10 to $20.

Northwest Airlines started the discounting over the weekend and other airlines quickly moved to match the prices, spreading the sale to virtually the entire country.

The sale cannot be applied to flights on the Sunday after Thanksgiving, Dec. 23 or Jan. 2. The last day to travel on a discounted ticket is Jan. 15.

Northwest said round-trip fares between Boston and Chicago will be $238, a 31% discount, for tickets purchased by Friday. One of the largest discounts, 39%, is on round-trip flights between Los Angeles and Seattle, which will cost $218.

As usual with discounts aimed at leisure travelers, the tickets are non-refundable, must be bought at least 14 days in advance and require a Saturday night stay. Travel must take place by Jan. 15, and tickets must be purchased by Friday.

Other airlines, including American, Delta and United, said they will spread Northwest’s fare cut to virtually their entire domestic route networks. United’s discounts on routes where it does not compete with Northwest are between 23% and 33%, spokesman Joe Hopkins said.

Separately, major airlines except Northwest matched an increase on selected fares by United Airlines. The increase raises round-trip fares about $20 on trips of more than 1,000 miles and will not take effect on 14-day advance purchase tickets until this weekend.