Airlines to Raise Fares This Week : Travel: The price hike amounts to between $10 and $30 on all routes of the nation’s major carriers. It begins Thursday.

Major airlines plan to raise fares between $10 and $30 on all their routes Thursday, one month after a similar increase ended a summer of cut-rate airplane tickets, airline officials said Monday.

The latest increase would amount to about 5% and counters expectations that the sluggish economy would lead to a shortage of passengers during the typically slow winter months and another round of fare discounting.

Recent traffic figures show increases over last year, rather than a dramatic drop, after last month’s conclusion of a half-price ticket sale, said an executive at a major airline, speaking on condition of anonymity.

“It’s a realization that costs continue to exceed revenues. . . . At some point you have to step up to that realization,” said Tim Smith, spokesman for American Airlines, which plans to go along with the increase initiated by Continental Airlines.

The fare hike keeps intact a move toward basing fares on mileage, rather than the demand for seats on particular routes, Continental spokesman Richard Danforth said.

The increase comes as several airlines decided to match a three-day promotion by USAir to waive advance-purchase requirements for its cheapest tickets. USAir is trying to rebuild its customer base after last week’s machinists union strike.

Officials at USAir did not immediately return telephone calls regarding Thursday’s increase. One airline executive said competition was still tough enough that USAir could doom the increase by refusing to follow.

Other airlines, including United, Delta, TWA and Northwest, went along with the increase.

America West matched the hike on routes where it competes with United and was studying the other increases, spokeswoman Daphne Dicino said.

Fares last went up across the country on Sept. 11, after several attempts to increase rates were scuttled when one or another airline refused to go along. The airline industry amassed huge losses in the April-June quarter, and more losses are expected when results for the three months ended in September are announced.

Airlines are supposed to make money in the spring and summer to carry themselves through the traditionally lean fall and winter months.