Dublin Airport was one of three hit by the air traffic controllers' action
Up to 20,000 passengers have faced disruption at three Irish airports, as air traffic controllers staged a four-hour strike.
Aer Lingus cancelled 64 flights, while Ryanair cancelled a further 52.
A dispute over work practices led to the industrial action by controllers at Dublin, Shannon and Cork Airports.
The airports shut down between 1400 and 1800 GMT while controllers attended mandatory union meetings. Union Impact has warned more stoppages are possible.
The meetings were called following the suspension of a number of controllers from Dublin and Shannon Airports for failing to cooperate with the introduction of new technology.
New work practices
After Wednesday's action, a spokesman for the trade union Impact said: "In the event that those suspended workers are not immediately reinstated and there are further suspensions, then the likelihood is that there will be further work stoppages."
Earlier, the union said the issue of new work practices was under discussion at the Labour Relations Commission and staff should not be suspended while negotiations were ongoing.
However, the Irish Aviation Authority claims that Impact told controllers not to cooperate with the introduction of a number of new technology projects unless they were given pay rises.
Taoiseach Brian Cowen said he hoped both sides would use industrial relations bodies to resolve the dispute.
He said the travelling public should not be inconvenienced over whatever differences exist at the airports.