BY ERIC TORBENSON Pioneer Press Northwest Airlines tweaked its frequent flier program Tuesday, wiping out "blackout' dates but also boosting the minimum miles needed for free travel. But within hours, American Airlines, which said last year that it would eliminate blackout dates in 2003, accelerated its plan and said that it would lift its restrictions by Feb. 1, one month before Northwest. The airline will allow a limited number of frequent flier tickets on 14 days -- sprinkled around major holidays -- that previously weren't allowed. Observers say Northwest is the first to make this move, and expect other programs may follow suit. "I can honestly say that Northwest Worldperks is the only frequent flier program in America with no blackout dates,' said Randy Petersen, a frequent flier guru and head of Inside Flyer, a magazine and online service that closely watches the programs and their changes. "If you're looking to book on those dates that are now open, I'd act fast because it's first come, first served.' Airlines picked the dates because they figured to be high-volume days where frequent flier seats would only cost the carrier lost revenue from a potential paying passenger. Northwest research showed that its sophisticated pricing computers could set aside a few free seats without costing the carrier money. Even on the busiest flying days, some seats were flying empty, Northwest said. The blackout dates end as of March 1, and a bigger change begins June 1 when "off-peak' awards granted during slower winter months will go away. Northwest is also scrapping its off-peak domestic travel policy, which allowed travelers with 20,000 frequent flier miles to fly free. That's 5,000 less than normal. The 20,000-point component has been a focus of the carrier's marketing. The airline expects some backlash, said Beth Shultis, vice president of marketing programs and worldwide advertising. "I think some people will be disappointed,' she said Tuesday, but the changes help simplify the program and the airline's research showed travelers were booking more trips over the full year instead of concentrating in the off-peak months to save a few points. The changes will likely benefit heavy users of the program and the carrier's "elite' fliers, who often rack up more points than they can redeem. Elites who buy business class or first class tickets will now get an extra bonus that helps them keep their status on Northwest. For less active users who save up points over time, the hurdle to get free travel rises another 5,000 points, but that's where most major carriers have had their lowest free trips awards for some time. Some signs of upset emerged online Tuesday. Some Worldperks regulars who post on FlyerTalk message boards called for the creation of a site called "saveworldperks.com' that would urge the repeal of the most recent changes. The changes also mirror actions at Northwest partner Continental Airlines, which said earlier this month that it would end its 20,000-point "off-peak' awards, also on June 1. Shultis emphasized that though the two programs have reciprocal benefits, each carrier makes independent decisions about its respective frequent flier program. Continental has not announced whether it will dump its blackout dates. Onepass remains the perennial favorite of frequent fliers according to Petersen's research, but Northwest's program is gaining and in some ways exceeds Continental's. He lauded Worldperks' online capabilities - giving statements out online and being first to let travelers book award travel online - as setting it apart. Northwest's elite fliers seem to get upgraded more frequently than elites in other programs, he said, though many still say Northwest falls short in the service area, Petersen said. "On paper it's as good a program as any, but in the past it's been the delivery of the product where some say Northwest falls a bit short,' he said. In a concession to frequent fliers, Northwest will give 250 frequent flier miles for flying on a Cybersaver fare. Last spring the carrier stopped giving mileage credit for the heavily discounted fares, lighting up message boards with protest. Northwest will also allow members to purchase up to 7,500 Worldperks points per year to help reach award levels or to help others increase their balance. Details on how much the points will cost weren't available. Shultis says Worldperks had great appeal before the most recent changes and should be even more attractive without the blackout dates. "We took a close look at the program and found that one of the irritations we could see was that over time there's been several layers of changes to the program, and we thought about ways that it could be clarified a bit,' she said. Leo/ORD