Alaska Airlines and Japanese Airlines have strengthened their codeshare and loyalty program partnership to offer more connecting flight options for JAL customers.
The expansion includes Virgin America routes following the successful completion of its merger with Alaska.
It gives JAL customers more flight options and access to San Francisco and Los Angeles.
Reservations for the extra codeshare flights went live this week.
"We are pleased to offer our customers more routes and destinations with our new partnership with Alaska Airlines," said Hideki Oshima, JAL executive officer, International Relations and Alliances.
"This expanded cooperation allows JAL to strengthen its own presence throughout the U.S."
JAL entered into a commercial partnership with Alaska Airlines in June 2016 before the Virgin America integration was finalized.
New Japan Airlines codeshare routes with Alaska include transcontinental flights from San Francisco to Boston and Newark.
