It took me all of 2 seconds to find their baggage policy on their website.

http://hawaiianair.custhelp.com/app/...detail/a_id/80

Specifically it says about carryon

CARRY-ON BAGGAGE:

Each ticketed passenger is currently limited to one piece of carry-on baggage and one personal item. You may check your stroller or car seat at the gate. Car seats, bassinets, infant carrying seats, or strollers are all accepted as check-in baggage, in addition to the free baggage allowance for the accompanying ticketed adult passenger, as long as traveling with the child. (There is no separate baggage allowance for infants held in a passenger's lap.)

These items may be carried on the aircraft as your one-piece of carry-on baggage allowance, provided the item can properly fit in the overhead compartment or stowed beneath the seat in front of you. In addition to the one-piece carry-on baggage allowance, you may also carry on one personal item such as a purse, briefcase, laptop computer, backpack or similar item.

When flights are full, HA reserves the right to stow Carry-On Baggage in the cargo compartment of the aircraft. Carry-on baggage may be limited further by aircraft type or storage availability.

Hawaiian Airlines operates the B767 aircraft between Hawaii and the mainland/South Pacific and B717 aircraft for interisland travel. Your carry on baggage should be no more than 45 linear inches, or 9"x14"x22" (H+W+L), and weight no more than 25 pounds/11.5kg.

The following items are not included as part of the carry on baggage limit.


- a handbag or pocketbook
- an overcoat or wrap
- a foot rug
- an umbrella or walking stick
- a camera and/or a pair of binoculars
- a reasonable amount of reading matter for the flight
- an infant's food for consumption enroute
- a collapsible wheelchair and/or crutches and/or braces or other prosthetic device on the same flight with passenger dependent on the device.
- any assistive device or mobility aid
Your primary storage area is the space under the seat in front of you. The overhead compartments are on a first come, first serve basis and are for all passengers. If your carry on item is unable to be safely stored under the seat in front of you or in the overhead compartment, or if all storage areas are full, you may be asked to check in your baggage for pick-up upon your arrival.

So based on their published policy, regardless of whether you intended to check your bags or not, you were over the limit and you should have paid.

Honestly, let this drop. It's a bit like being a kid and thinking your sibling has a bigger glass of soda than you do. I can understand your frustration, last time I was at HNL they were going around trying to take bags of people. The gate agent tried to persuade me to check my carryon, even though it was well within the dimensions, yet there was a family across from me with 8 carryon pieces between 3 of them and they appeared to get away with it. What peeves me even more, is it is the families that will preboard with their never ending carryon that hog the space.

One thing we all know is that airlines are allowed to make their own policies and decide what they charge customers.