Aloha only had 13 aircraft flying inter-island.

Are you saying that 4 aircraft can't pull enough passengers from 13 aircraft to put a dent in Aloha's razor-thin profit margins?

Those 4 50-seaters represented 12% of Aloha's CASM. I'm sure Aloha wasn't making a 12% profit to cover the potential loss. At a more reasonable 2-3% profit margin, the 12% loss would have crushed Aloha.

Of course you'll have to search JO's laptop to find the real numbers.