Hawaiian Airlines is ready to take the next step in launching a regional turboprop subsidiary after reaching agreement with its unions.

The carrier has signed a letter-of-intent (LOI) in a deal for an unspecified number of turboprops. “Over the long term, we envision three to six aircraft” in the turboprop subsidiary, a Hawaiian spokeswoman tells Aviation Week.

These turboprops will be used aircraft and purchased, rather than leased.

The spokeswoman, however, says the carrier is “constrained from going into deep detail” about the aircraft deal due to confidentiality requirements in the LOI.

While the aircraft type is not being revealed, the carrier’s collective bargaining agreement restricts turboprop operations to aircraft with no more than 69 seats. Hawaiian is “looking for aircraft that seat fewer than 50, as we think that’s the right seat configuration” for the routes it has in mind, the spokeswoman says.

The carrier has been considering a turboprop operation for at least a couple of years, says the spokeswoman, who notes that “we had to work out agreements with the pilot and flight attendants unions.” The LOI is the “next step” in the process.

Hawaiian does not even have a “ballpark estimate” for when the turboprop flights would begin, and no schedule has yet been set, the airline spokeswoman says. However, in general, the carrier will be looking at routes that “cannot be served economically, operationally or both” by its fleet of Boeing 717s. Destinations on the shortlist include Molokai, Lanai and West Maui.

News of the LOI was revealed as part of a new inter-island fare plan. The carrier says the aim is to establish a subsidiary to “serve routes not currently in Hawaiian’s neighbor island system.” It will enable Hawaiian to “further expand capacity with daily flights to rural areas.”