Up to 1,500 jobs are at risk at Ryanair.
The airline says it is because of the risks of a no-deal Brexit and the Boeing 737 Max planes being grounded.
In a video sent to workers, Ryanair's chief executive Michael O'Leary outlines plans to cut the number of staff and planes.
He says they currently have 900 pilots and cabin crew that are not needed and that 600 will also need to be laid off by next summer.
This comes after Ryanair announced on Monday a fall in profits of 21%.
Michael O'Leary says one of the reasons cuts are needed is because of uncertainty over a no-deal Brexit.
The grounding of the Boeing 737 Max after two fatal crashes is also having a significant impact.
It is not yet known how many of the cuts will affect Irish workers but a final decision is expected by the end of next month.
The Irish Airline Pilots Association says it is in discussions with Ryanair to find out more.
