CFM56 engines don’t like short flights, the engines need time to cool down. M
That’s why you don’t see CFM56s on interisland flights.
WN and AK both have no issue at all running short flights and quick turns all day every day from routes like GEG-SEA... Not to mention international airlines that run these.
WN already operates many nonstop routes within the contiguous U.S. that are shorter than LIH-KOA, including ATL-GSP, ATL-BNA, AUS-DAL, AUS-HOU, BWI-ISP, BWI-ORF, BWI-PIT, BWI-RDU, BUR-LAS, MDW-CVG, MDW-DTW, MDW-GRR, MDW-IND, MDW-STL, DAL-HOU, DAL-OKC, DAL-SAT, DAL-TUL, DSM-STL, FLL-MCO, FLL-TPA, HOU-SAT, MCI-STL, LAS-LGB, LAS-LAX, LAS-ONT, LAS-SNA, LAS-PHX, LAS-SAN, OAK-RNO, and RNO-SJC.
In addition, a few of the existing WN nonstop routes within the contiguous U.S. such as ATL-GSP, AUS-HOU, BWI-ORF, and MDW-GRR are shorter than the HNL-KOA nonstop route.
WN is certainly able to operate LIH-KOA and HNL-KOA nonstop service on 737-800 planes since WN already operates 737NG planes on nonstop routes within the contiguous U.S. that are shorter than LIH-KOA and HNL-KOA.