Northwest Airlines and United Airlines have recently been locked in a bitter bid for frequent flyers, offering members of their respective programs double miles toward elite status.

United picked the fight, offering double miles beginning Aug. 22 — two days after Northwest’s mechanics went on strike. The offer was targeted, however, to email recipients in Northwest’s core territory in the upper Midwest.

United and Northwest are the two biggest U.S. servers of the Asian market, and Northwest considers United to be its main competitor.

United spokeswoman Robin Urbanski told The Associated Press that the promotion was purposefully aimed at Northwest.

“Those are just a part of the efforts that United is doing to help any passengers that are disserviced by the Northwest strike,” she said. “So it’s simply about helping customers.”

Both promotions allow the miles to count for elite status and the accompanying first-class upgrades and early boarding.

But while United’s offer appears aimed at a narrow group of travelers in the Midwest, Northwest’s offer was good nationwide. The United offer ended Sept. 30, while Northwest’s ends Oct. 9.