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 expanding its presence at San Diego International Airport with the introduction of three new nonstop routes and the addition of more flights to some popular destinations.

In the latest aviation developments, Alaska Airlines plans to end service this fall on three domestic routes from San Francisco and Los Angeles but will continue to grow at San Diego, adding new routes and more flight frequencies;