There's a restaurant on the ground floor of HNL, off of the Diamond Head(East) courtyard that serves mainly airport personnel. The great thing about this restaurant is that the prices are about half of what is charged one floor above. If you go in and don't make a disruption in the flow of the place (carry-ons blocking the aisles and taking up chairs for example) the staff will serve you with aloha AND you'll save a lot of money. Just remember that the airport/airline staff are on timed breaks, so try not to get in their way!
Do you know the hours they're open? It would be great if I could grab breakfast there before my morning flights or grab dinner on my return. I usually just bring a granola bar from home as I'm sick of the food at the inter-island terminal. I'll be looking for this place when I fly back to HNL this afternoon. I'm always glad to hear about more places where I can stuff my face!
I'm not sure of the exact hours, but I've had breakfast here many times. Next time I'm there I'll check the specific hours and report back.