Southwest Airlines, whose long-awaited entry into the Hawaii market has been delayed by the partial federal government shutdown, said its new service won’t be able to start any earlier than March and most likely will be postponed until the second quarter.

The Dallas-based carrier says the government shutdown has prevented Federal Aviation Administration regulators who must complete the certification process from returning to work.

“If the shutdown ends within a week, I think we have a reasonable chance of beginning service in the first quarter of 2019. Otherwise, it will likely be in the second quarter,” Chief Operating Officer Mike Van de Ven said Thursday during the company’s earnings call in which the airline said the shutdown so far has cost the company $10 million to $15 million in revenue.

Chairman and CEO Gary Kelly said Southwest doesn’t have any plans to add any international routes this year because Hawaii is the airline’s “top new market.”

Southwest initially had planned to begin selling tickets last year for Hawaii serv- ice as it waited for the FAA to complete its certification. But the government shutdown roiled those plans.

“Mike had planned, once we started selling, that we would be flying sometime in February,” Kelly said. “So, if we get started again with the FAA, let’s say Feb. 1, I think you can roughly allow a month and then we would be able to get our certificate and sell, and then we would be flying in the following month. And it just rolls. … It’s somewhere around six to eight weeks, I would say, from the time that he starts working with the FAA to finish to the time that we would be flying.”

Kelly said Southwest is increasing the size of its overall fleet by 25 aircraft this year and that Hawaii is going to play a big role in how those planes are utilized.

“We’re at record fleet numbers this year, and we’ll be adding a net of 25-ish in 2019,” Kelly said. “What do we do with 25 airplanes? We’re going to Hawaii. We’re going big. That needs to be the focus. And it kind of crowds out expansion in other areas like international.”

Southwest said last year it initially plans to fly to Hawaii from the California cities of San Diego, Oakland, San Jose and Sacramento and then add interisland routes that include Maui, Hawaii island and Kauai.

“When we first start out to Hawaii, we’re just going to be focused on the mainland to Hawaii and flying for a period of time,” Van de Ven said. “(It probably will be after) a couple of months of service before we get into the interisland flying.”

Southwest said it will ramp up its Hawaii service throughout the year and initially start from one location on the mainland before branching out.

“As we get more Hawaii locations out there, we’ll have more options then to connect that interisland flying,” Van de Ven said. “And that’s why we’ll launch with the mainland service first and then follow on with the interisland flying.”

Southwest, which spent much of the conference call talking about Hawaii, said its earnings fell 63 percent in the quarter to $654 million from $1.75 billion in the year- earlier period. The $1.17 earnings per share beat analysts’ consensus estimate of $1.06. Revenue rose 8.5 percent to $5.7 billion.