Cape Air has discontinued off-season flights between Hyannis and the Island due to low demand, the Hyannis-based airline announced Monday.

The change is effective Oct. 22.

“The passenger numbers just aren’t there to sustain a business,” said Michelle Haynes, spokesperson for Cape Air. “For us to continue offering the service that the passengers were just simply not signing up to fly . . . didn’t make good business sense.

Only four passengers had confirmed reservations on the route after Oct. 22, Ms. Haynes said. Those passengers will be refunded, and three other customers who fly the 15-minute commuter route almost every day have also been notified individually, she said.

Cape Air flies Cessna 402 nine-passenger aircrafts to all of their destinations.

“When I say it was a quiet route on the off-season, put a capital Q on quiet,” she said.

Cape Air service to Boston, New Bedford and Nantucket will continue year-round.

“The most important part of our service in the off-season, the most important link, is that link to the national air transportation system” at Logan Airport, she said. “Whether we have . . . maybe one or two passengers in the plane in February, that service is going to continue. We are always going to maintain it.”

Cape Air is the only airline that services the Vineyard in the off-season. Delta, Jet Blue and US Airways fly to and from the Island beginning in May.

Alternate travel options include the Steamship Authority ferry from Woods Hole, she said.

Service between the Island and Hyannis will resume on May 22, 2014, when demand for that route is higher.

“Cape Air is continuing service to Martha’s Vineyard when the passengers are there, and absolutely we will be in full service Memorial Day weekend,” Ms. Haynes said.

The airline has been in business for 25 years, and has been flying year-round to the Island almost since the beginning. Cape Air service between Martha’s Vineyard and Hyannis began with the purchase of Edgartown Air in October of 1990. Since then, the airline has expanded nationally and internationally, with plans to offer service to six cities in Montana in the coming months. Cape Air is now considered the largest independent regional airline in the United States.