Hawaiian Airlines flight attendants held a major labor demonstration on Wednesday at Daniel K. Inouye International Airport over protracted negotiations for a new contract.

The contract between Hawaiian Airlines management and the flight attendants, who belong to the Association of Flight Attendants union, became amendable on Dec. 31, 2016. The company and its flight attendants union have been in mediation since the fourth quarter of last year. So far, two protests including the one Wednesday have been held in Honolulu and a third protest was held in Los Angeles International Airport.

Sticking points are mostly about wages and benefits. The union says that on average Hawaiian’s top-scale pay rate for attendants is about $20 below what other carriers are offering. The last raise for Hawaiian flight attendants was in March 2016, which brought starting pay to $22 an hour. Top-scale workers, who have 20 years on the job, make $55 an hour.

While the hourly wages sound high to some, flight attendants say they only get paid when the aircraft is moving and are only guaranteed that they’ll be paid for 75 hours a month. At top scale, that means Hawaiian flight attendants are only guaranteed $49,500.

Another union concern has been that Hawaiian’s retirement plans do not provide enough continuity of medical benefits.