FILE PHOTO - A Southwest grounds crew member pats the nose of a Boeing 737-700 plane as it comes to a stop at its gate at William P. Hobby Airport in Houston, Texas, February 20, 2019. REUTERS/Mike Blake

CHICAGO (Reuters) - Southwest Airlines Co said on Wednesday it won approval from the U.S. Federal Aviation Administration to begin flying to Hawaii from California, clearing the way for the low-cost carrier to move forward with a key part of its 2019 growth plan.

Dallas-based Southwest, one of the largest U.S. domestic airlines, said it would publicly announce the timing for selling tickets and inaugurating flights to the Hawaiian Islands in the coming days.

Southwest will fly its Boeing 737 fleet from Oakland, Sacramento, San Diego and San Jose, and plans to service Honolulu on Oahu, Kahului on Maui, Kona on Island of Hawaii, and Lihue on Kauai. The company also plans to fly between the Hawaiian Islands.

It will compete with American Airlines , Delta Air Lines, United Airlines, Alaska Airlines , and Hawaiian Airlines on the new routes, though analysts said it remained to be seen whether Southwest’s entrance would drive down other carriers’ fares.

Southwest, which first unveiled plans for the new service in 2017, had hoped to begin selling tickets in January. But those plans were delayed due to a 35-day partial U.S. government shutdown, which halted a lengthy federal certification process for jets that fly over water for an extended period.

The FAA said that, as standard practice, it will increase its surveillance of Southwest’s operations for six months as service begins.

The Hawaii approval comes as the carrier continues to clash with its mechanics over a doubling of out-of-service aircraft that has forced it to cancel hundreds of flights since Feb. 15.

Southwest and its mechanics union have been in contract talks for more than six years.

Flights canceled by Southwest continued to account for more than a third of the total across the United States on Wednesday, according to FlightAware.com.