Makani Kai flies only single pilot and are the ones who had the crash of Kalaupapa, killing the Director of Health & Human Services in Hawai'i because the pilot gave her the wrong sized life vest (infant).
They do have only single-fares and aren't on the same page as Mokulele.
Fwiw, I ended up buying on Mokulele. My time with friends is more valuable, so no TSA, easy parking, and easy off justify the $126 fare + bag fees versus taking Hawaiian.