Nholidaycheckaadvantageow, American Airlines frequent fliers can earn 70 miles per review left for up to 10 review per month making it 700 a month if you’re a busy traveler. This is a perfect way to keep American AAdvantage miles active on those family accounts that haven’t had any activity for a while. One review will extend the validity of the miles by 18 months. Airberlin, Etihad and Lufthansa frequent fliers have been able to earn 100 to 150 miles per hotel review left on HolidayCheck.com website but they are finally getting around to allowing AAdvantage flyers in on the action!