here is my tips on Honolulu rentals, Hawaii rentals tend to show a little wear.. I know we are in a hurry but take an extra minute and fill out the dent and scratch chart, I like to put a mark on every side front to back just to cover everything.
A couple more, Oahu is not that big, and everyone drives slow, there is no way you will use a full tank of gas, so do not prebuy the tank. Just fill up in the end, the gas station at the airport seems to have fair prices, but they will not be open super early or late.
2 more, never leave anything in your car, and this is not NYC, do not use your horn, ever.