Southwest Airlines begins interisland flying Sunday, challenging the monopoly that Hawaiian Airlines has enjoyed in that market for almost two years.

Southwest entered the Hawaii market March 17 with service between Honolulu and Oakland, Calif. It launches its initial interisland service Sunday morning with flights between Honolulu and Kahului.

Airline analysts will be watching closely to see what impact Southwest’s interisland flights will have on Hawaiian Airlines’ historic stronghold in the interisland market, which it has owned since the November 2017 shutdown of Island Air. The market also proved too tough for Aloha Airlines, which stopped flying in 2008, and go!, which ended Hawaii operations in 2014.

Southwest kicked off its serv­ice to Hawaii with low initial pricing. However, Southwest President Tom Nealon said Thursday the carrier “is moving up the price where to what we consider to be normal pricing levels, and we’re seeing very strong demand in bookings.”

Heightened competition at times will probably continue the price war between the carriers. Still, at this juncture the advantage for consumers is probably more about having expanded choices. Hawaiian has a far more robust schedule of neighbor island flights. It’s also got a reputation for punctuality and service that attempts to connect passengers to a Hawaiian sense of place. Passengers can choose their seats in advance, but they’ll have to pay for extras like baggage and change fees.

Southwest’s interisland schedule is far more limited, and passengers don’t get to select seats early. However, the carrier allows passengers two free bags and never charges change fees. Southwest is new to the Hawaii market, but it’s known for its own fun- loving culture. For example, plenty of staff members dressed up like leprechauns for Honolulu’s St. Patrick’s Day launch.

Nealon said early feedback from Hawaii customers has been “absolutely exceptional.”

“Their satisfaction with the in-flight experience is actually higher than the rest of our system,” he said. “I think this clearly speaks to the strength and the quality of our economy product.”

Nealon said Hawaii serv­ice exceeded Southwest’s expectations in March. Despite a short two-week booking window, Southwest’s first flight between Oakland and Honolulu sold out quickly.

“We have more Hawaii service to come, and we are very pleased with how these markets are performing. And the expansion of Southwest service into Hawaii is our primary route development focus for 2019 to 2020, and that will also include more interisland serv­ice,” he said.

Southwest reported Thursday that its first- quarter profit fell 16% to $387 million. The carrier reported adjusted earnings of 70 cents a share — 9 cents above the forecast from analysts surveyed by Zacks Investment Research.

It didn’t help Southwest’s first quarter that its Hawaii start was delayed a month when the federal government shutdown interfered with its pursuit of Federal Aviation Administration certification. Then came the FAA’s March decision to ground Boeing 737 Max 8 and Max 9 aircraft in the wake of deadly crashes involving Lion Air and Ethiopian Airlines.

Southwest has 34 Boeing 737 Max aircraft but doesn’t yet use the aircraft for its Hawaii service.

A lengthy labor dispute, which was only settled as Hawaii service began, also resulted in the mass grounding of planes from unanticipated maintenance write-ups.

Between the government shutdown, labor issues, the FAA Max aircraft groundings and weather issues, Southwest canceled more than 10,000 flights during the quarter, with Max-related cancellations expected to extend through Aug. 5, putting some of its growth plans on hold.

Gary Kelly, Southwest’s chairman and CEO, said Thursday during a podcast that the carrier’s Hawaii plans aren’t affected — with one exception.

“Because we have reduced our flight schedule this summer, we had planned to add more flights to Hawaii this summer and probably will delay the timing of launching those until we have the Max back in serv­ice, simply because we’re short on airplanes overall,” Kelly said.

Still, Kelly said that “Hawaii expansion is off to an exceptional start.”