The airports at Shannon and Cork saw few passengers as the one-day strike by Aer Lingus clerical and operative staff took hold.
At Shannon Airport, 3,500 passengers booked on Aer Lingus were affected as 400 staff took strike action.
A total of 33 flights were cancelled. These included 26 Aer Lingus and seven others which depend on services provided by the national airline.
There was a great rush from 7.30 a.m. until noon, when six east-bound Aer Lingus transatlantic flights which had left before midnight operated normally. They brought 1,500 passengers from New York, Chicago, Baltimore, Boston and Newark.
Yesterday evening, all westbound Aer Lingus Airbus jets flew out empty to provide for this morning's incoming transatlantic passengers. Some 400 of the cabin staff which provides these services are based in the Shannon region.
Over 100 Aer Lingus clerical and administrative staff members were on the picket line in Cork yesterday, and all 13 of the airline's scheduled flights out of Cork airport were cancelled.
Up to 2,500 passengers had their flights cancelled in Cork as SIPTU clerical workers picketed in an effort to win a new pay deal similar to the one achieved by cabin crew after their strike action.
A spokesperson for Aer Lingus said the company was pleased with the co-operation it had received from other airlines in Cork in arranging substitute flights for passengers. However, concern was expressed about the damage the strike was doing to the credibility of the company.
"The other airlines in Cork Airport have helped ease the tension considerably. We are very thankful for their co-operation. However, this is a black day for Aer Lingus. We are making a genuine effort to keep the public informed about the situation but are concerned about the damage this does to our brand," said Mr Declan Conroy, public relations manager.