Hawaii’s largest interisland air cargo company, Aloha Air Cargo, has bought two new planes to diversify its fleet.

The company has bought two Saab 340 aircraft it anticipates will be put into service between April and June. The new turboprop planes represent a 15 percent increase in the carrying capacity of Aloha Air’s fleet presently made up of four Boeing 737-200 jets. Each Saab plane has one-third the cargo capacity of a 737-200.

Aloha Air said the addition will provide more flight flexibility and efficiency.

Aloha Air Cargo carries close to 70 percent of interisland air freight. The company was created in 2008 though the purchase of cargo operations of Aloha Airlines by Seattle-based Saltchuk Resources Inc., which owns interisland ocean cargo transportation firms Young Brothers and Hawaiian Tug & Barge.