USAir will compete with a frequent-flyer plan.

USAir became one of the last remaining major airlines to offer the plan, which has “become a permanent feature embedded in airline marketing” and necessary if the airline is to remain competitive, said Randall Malin, the Washington-based airline’s executive vice president-marketing. Malin acknowledged that, in recent years, USAir has lost some business travelers who have gone to other carriers who offered frequent-flyer plans.