Delta SkyMiles members can earn double miles on all flights between Seattle and San Francisco, Las Vegas and Los Angeles booked by Dec. 31, 2013 for travel through Oct. 31, 2014. Be sure to register at http://insideflyerus.wpengine.com/link/?9991 first. Unlike many promotions where you have to register before you travel, the fine print states you must register prior to booking. The double miles offer is valid on all Delta and Delta Connection-marketed and -operated flights between eligible cities. Travel can begin or end in any city, but you will only earn double miles on the eligible Seattle segments.

Delta is beefing up its Seattle presence and beginning March 29, 2014, the airline will offer six new daily nonstops between San Francisco and Seattle, increasing to seven daily flights on June 5, 2014. Two additional flights from Las Vegas will be added on Jan. 6, 2014, bringing the total number of flights to three. And there will be seven daily nonstops (from five) from Los Angeles beginning June 5, 2014.