Here is a very short term promo from Hawaiian Airlines. It actually started on the 28th of May but we only found out about it today. You must register and book by tomorrow if you want to take advantage of it! The offer is for Double HawaiianMiles when you fly on Hawaiian Airlines between Honolulu and Sendai or Sapporo in Japan. The offer is good for economy or business class flights until the end of the year. Simply register online and then book your flight at hawaiianair.com by June 3rd!