A number of Aer Lingus flights were also cancelled Saturday and Sunday because of an increase in Covid-19 cases among staff.
Three return flights were cancelled by the airline on Saturday had been announced.
These flights took place between Dublin and London, Dublin, Amsterdam, and Knock.
Three Sunday return flights have been cancelled.
These were flights between Dublin, Lisbon, Dublin and Milan, Dublin and Amsterdam.
Two return flights from Lyon to France on Saturday were also cancelled due to industrial action by ground handlers at Lyon Airport.
Aer Lingus cancelled nine of its return flights on Friday and one of its direct flights on Friday because of Covid-19 cases.
One return flight from Bordeaux to France was also cancelled on Friday due to industrial action in France.
Also, there were many cancellations during the week.
The airline apologized to the passengers who were affected.
It stated that teams were working to accommodate them on the "next available services as efficiently and effectively as possible".
Aer Lingus stated that it had "anticipated the return to demand for travel after Covid restrictions were lifted and built appropriate buffers in our plans to deal with any additional disruption."
It stated that system pressures and ongoing problems at certain airports as well as third-party suppliers have caused significant operational challenges. This has been exacerbated by an increase in Covid cases in the recent days.
