Alaska Airlines Mileage Plan members who sign up for the new Alaska Airlines Visa Signature credit card will earn 20,000 bonus miles upon approval, one roundtrip $50 companion ticket and then another every year, and complimentary concierge service 24/7. The Bonus mile offer is a vast improvement over the 5,000-mile bonus most recently offered for an Alaska Airlines credit card and the richest offer to date for the airline. Cardholders will earn one mile for every dollar of purchases except when purchasing Alaska Airlines or Horizon Air tickets and vacation packages when members will earn two miles per dollar. There is no limit to the number of miles a member may earn in a year. Cardholders will also get two Board Room passes upon approval and a 2,000-mile anniversary bonus. The cost for the card is $75 per year and the promotion is valid through Dec. 31.