Washington travelers are in for hefty discounts as the springtime airline-fare war heats up and some major carriers slash their fares as much as 75 percent.

American Airline's "Spring for Less" sale kicked off yesterday offering fares $20 to $40 below its previously lowest rates. The new fares will be in effect between April 1 and May 22 on its domestic flights to nearly 100 cities.

Republic Airlines, Northwest Airlines and United Airlines are offering similar discounts, with slightly different restrictions. Other discounts may be announced soon.

American's Washington-to-Dallas fare will fall to $198 round trip during the peak days of Thursday, Friday, Sunday and Monday. On the off-peak days, that fare will drop to $158 round trip.

American's current coach fare from Washington to Dallas is $660 round trip, its lowest peak super saver is $238 round trip, and its best off-peak round trip is $198.

American's round-trip fare to Los Angeles will drop to $278 during peak days and $238 for off-peak days. Its regular coach fare is $980, its peak super saver is $318 and its off-peak super saver is $278.

American's spring fares, however, have more restrictions than current fares. Passengers must buy round-trip tickets, reserve seats and buy tickets at least 30 days in advance and within 14 days of making a reservation, stay over a Saturday night and stay no more than 21 days. There is a 50 percent cancellation fee for off-peak tickets and a 25 percent fee for peak tickets.

Republic Airlines, Northwest Airlines and United Airlines are offering similar discounts with slightly different restrictions. United's round-trip ticket to Chicago falls to $158 for peak days and $118 for off-peak days. The regular coach ticket is $500, its peak super saver is $178 and its off-peak super saver is $158.

United has the same restrictions as American, except its penalty for cancellation of an off-peak ticket is 25 percent of the fare, rather than 50 percent.

Republic's Washington-to-Detroit spring off-peak fare will be $78 round trip, and the peak fare will be $98 round trip. The regular coach fare to Detroit is $420, the off-peak super saver is $98 and the peak super saver is $118. Republic's cancellation fee is a flat 25 percent.

Northwest's new round-trip fare to Minneapolis/St. Paul during peak days falls to $178, while its off-peak rate drops to $138.