Alaska Air Carriers Are Battling: A marriage of convenience between two Alaska air carriers has dissolved in a bitter divorce. Seattle-based Alaska Airlines and Anchorage-based MarkAir Inc., Alaska's largest in-state carrier, severed their cooperative relationship last month. The dispute began when MarkAir announced that it will launch daily service between Anchorage and Seattle, an Alaska Airlines stronghold. In response, Alaska Airlines abruptly ended its marketing agreement with MarkAir. Then MarkAir said it would fly to a number of other cities in Alaska that Alaska Airlines serves.