Alaska Airlines, building on its continuing expansion effort in San Diego, announced Tuesday it will add three new nonstop flights and significantly increase flight frequency for four of its more popular routes.

Alaska Airlines is launching three new nonstop routes from San Diego later this year, it was announced Tuesday.

Alaska Airlines is adding new nonstop routes to three destinations from San Diego, and increasing flights to popular destinations, making it the airline offering the most nonstop destinations at the San Diego Airport.