AP Style holds that you should not abbreviate “Hawaii” in datelines or stories. The Postal Code for Hawaii is “HI.”
Hawaiians
Hawaiians are members of an ethnic group indigenous to the Hawaiian Islands and are also called “Native Hawaiians.” Use Hawaii resident for anyone living in the state.
The state comprises 132 islands about 2,400 miles southwest of San Francisco. Collectively, they are the “Hawaiian Islands.”
The largest island in land area is Hawaii. Honolulu and Pearl Harbor are on Oahu, where more than 80 percent of the state’s residents live. Honolulu stands alone in datelines. Use “Hawaii” after all other cities in datelines, specifying the island in the text if needed.
Hawaiian Airlines in headquartered in Honolulu.
See also AP Style Datelines and AP Style State Abbreviations.