Aer Lingus has stopped paying 20 staff and continued to cancel flights in an escalating dispute over working hours.
A further ten flights are expected to be cancelled today, as the airline struggles to implement a new staffing roster.
As many as 1,500 passengers are expected to be affected by the dispute.
To date some 50 staff have refused to comply with the new roster system, which was implemented on Monday, with 20 removed from the payroll and relieved of their duties.
However, the former state-owned airline was quick to add they had not been sacked.
As the dispute continues the Irish Travel Agents Association (ITAA) called on Irish minister for transport, Noel Dempsey, to mediate in the case to avoid further damage to the industry.
Aer Lingus said a flight from Dublin to Chicago and its return leg had been cancelled, as well as a flight from New York to Dublin.
Yesterday the airline was forced to cancel a return flight to Boston.
A flight to New York and return route to Madrid will be operated by hired aircraft.
“Sole responsibility for these cancellations, and the corresponding disruption to customers’ travel plans, lies with Impact trade union members who continue to take industrial action despite 15 months of negotiation, agreement, clarification, conciliation and binding arbitration,” explained a statement.
In response the union argued new rosters are excessively onerous and have been imposed on staff in contravention of the Greenfield cost-saving agreement signed last year.
The union said it had referred the dispute to the Labour Court, but that a date for a hearing had not yet been set
The former state carrier has cut unprofitable routes, reduced staff and fuel costs to reverse losses threatening its survival.
It returned to profit last year.