Hilton HHonors members can earn double miles on American, Hawaiian, Delta or United when you book at any participating Hilton property in Hawaii through Feb. 28, 2015 for stays completed through Dec. 18, 2015. To be eligible for the promotion, Hilton HHonors members must request H9 or HH9 rate plan and book by Feb. 28, 2015. Stays must be completed by Dec. 18, 2015. Members must select Points and Variable Miles or Points and Fixed Miles as your Double Dip earning style in your HHonors profile. In addition, members must select American Airlines, Hawaiian Airlines, United Airlines or Delta Air Lines as your preferred Double Dip Points and Miles partner in your Hilton HHonors account profile prior to completing your stay. For more information, visit http://insideflyerus.wpengine.com/link/?11952 . There is no limit to the number of miles you can earn through the promotion.