Ryanair has announced it is cutting its Dublin-based fleet from 30 to 24 planes for the winter 2018 season, putting 300 jobs at risk.
The six planes will transfer to the carrier’s Polish charter airline, which it said was growing rapidly.
Ryanair blamed a downturn in forward bookings and airfares in the Republic of Ireland, partly as a result of recent rolling strikes by Irish pilots.
About 100 pilots and 200 cabin crew have been given 90 days’ notice.
The airline said their services “may not be required from 28 October onwards”.
It added that it would be offering transfers to Poland and possibly other bases, in order to minimise redundancies.
Earlier this week, Ryanair said its profits in the April-to-June quarter had been hit by higher wage costs as the airline faces strikes by staff over pay and conditions.
It said higher oil prices and a fall in fares also dented profits, which fell 20% to €319m (£285m).
Ryanair is facing more strikes. Cabin staff in Spain, Portugal, Belgium and Italy are walking out on Wednesday and Thursday, forcing the cancellation of 600 flights.
The airline’s chief operating officer, Peter Bellew, said its board had decided to allocate more aircraft to markets where it was enjoying strong growth.
“This will result in some aircraft reductions and job cuts in country markets where business has weakened, or forward bookings are being damaged by rolling strikes by Irish pilots.”
He added: “If our reputation for reliability or forward bookings is affected, then base and potential job cuts such as these at Dublin are a deeply regretted consequence.”
Ryanair fleet cuts put 300 jobs at risk