Mirroring a change by Continental we reported last month, Northwest Airlines WorldPerks members will have to spend more miles to get first class award tickets within or between the 48 contiguous U.S., Alaska and Canada beginning March 1, 2008. First class PerkSaver awards will be 50,000 miles, up from 45,000 miles and first class PerkPass awards will be 100,000 miles, up from 90,000. Members redeeming Northwest miles for flights on partner airline Continental will have to spend the increased mileage beginning on an earlier date, Feb. 1, 2008. Other flight award redemption amounts will not change.