Alaska Airlines will start daily service between San Diego, California, and Kahului, Maui, from 1 October 2010, and daily seasonal service between San Diego and Puerto Vallarta, Mexico, from 12 November.
The airline will also begin four-times-weekly seasonal flying between Portland, Oregon, and Kona, Hawaii from 12 November.
Alaska will deploy Boeing 737 aircraft for all the new services.
Horizon Air will start four-times-daily service between San Jose, California, and Los Angeles from 23 August 2010. All flights will be operated using Horizon's Bombardier Q400 turboprop aircraft.