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. The airline will begin offering nonstop service from San Diego to Phoenix on Aug. 20 and to Chicago O’Hare and Denver on Oct.

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.