Southwest Airlines [southwest.com] have $ 39 one-way airfares travelling to and from islands in Hawaii. Two examples I’ve attached is for Honolulu (HNL) and Maui (OGG) and Maui (OGG) to Kona (KOA). Other islands are available as well.

Travel Availability: daily through mid-February 2023

On Southwest Airlines, 2 bags fly free with free cancellation/changes. There is no advance seat selection. Want to see more travel deals? Click here or here.