Breeze Airways is adding a destination from Portland International Jetport before it has even begun service there. Shawn Patrick Ouellette/Staff Photographer

Breeze Airways hasn’t begun flights to and from Portland yet, but the carrier is already expanding service with Maine’s largest airport.

Utah-based Breeze said this week it will offer summer seasonal service between Portland and Islip, New York, starting June 28. Islip is about 30 miles east of New York City, near the south shore of Long Island.

The airline announced in February that it will begin year-round service May 17 between Portland and Tampa. Flights will begin May 19 to and from Charleston, South Carolina, and a route connecting Portland and Orlando is planned for September.

Breeze has also said it will offer summer seasonal flights between Portland International Jetport and both Pittsburgh and Norfolk, Virginia. Service to and from those cities begins June 2.

It’s “fairly unusual” for an airline to add flights to an initial schedule before service has even begun, said Zachary Sundquist, assistant director of the jetport.

He said airlines will typically gauge the reception among passengers during the first season they operate in a new location before deciding to make changes to the schedule. But Breeze officials told him that they’ve had strong advance bookings for the airline’s flights to and from Portland, and added the Islip flights to take advantage of expected strong seasonal demand.

Sundquist said airline officials are also talking to Breeze about adding more flights to and from Portland in the winter, but no decisions have been made.

Breeze studies data from the federal Department of Transportation to see where travelers are flying, and also looks at where they’re connecting through, or if they’re driving to a regional airport far from home, said Gareth Edmondson-Jones, a spokesman for the airline.

In Portland, he said, “the tickets have been selling like hotcakes,” and the airline expects passenger interest in traveling to Maine to rise sharply this summer, leading to the decision to add flights.

“There are a lot of people in New York and Long Island who want to visit Maine this summer,” Edmondson-Jones said.

While Breeze is reporting strong interest in its service, the only commercial passenger airline based in Portland appears to remain grounded.

Elite Airways, whose headquarters remain on Portland Pier according to the airline website, stopped flying last June after previously operating flights between Portland and White Plains, New York; Newark, New Jersey; and Vero Beach and St. Augustine, Florida. A series of flight cancellations left passengers in the lurch, although late last year the airline issued some refunds.

In some Florida markets, Breeze has supplanted Elite as a regional carrier.

Elite officials haven’t returned messages left at the company’s Portland offices and now a switchboard there answers with a recording saying that the phone number is not set up to receive calls. A reservations website is still online but is not functioning.

A message at the top of the website page reads, “Elite Airways will be announcing new service soon.”

Sundquist said he talked regularly with Elite officials in the fall and early winter about resuming service, but hasn’t heard from the carrier since early January. In the last conversation, he said, Elite officials echoed the notice on their website, saying “they were looking forward to announcing a schedule in the future,” he said.