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 has announced the launch of a year-round, nonstop service between Phoenix Sky Harbor International Airport (PHX) and San Diego International Airport (SAN), starting August 20. The Seattle-based carrier,

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