It will be interesting to see how the future pans out for Hawaiian. They are regarded as a 'lower' cost carrier and heavily reliant on the leisure customer. They have expanded aggressively in recent years. They do not have the higher yield traffic that Delta and United enjoy yet their pilot salaries are within reach.
I guess the cabin crew will be next, then ground workers.
Hawaiian filed for Chapter 11 protection in 1993 and again in 2003. I am willing to take bets on HA filing for Chapter 11 again before 2020.