Ryanair pilots will stage fresh strikes for several days from 18 to 29 September, the BALPA union has announced.
This follows the ending of the latest walkout over pay and working conditions, which caused little disruption to holidaymakers on the low-cost airline.
British Airline Pilots Association bosses now say there will be a 48-hour walkout on 18 and 19 September, as well as 24-hour stoppages on 21, 23, 25, 27 and 29 September.
Pilots have been on strike for the last three days but Ryanair flights have continued to run as scheduled after the airline was able to use contractors and foreign crews for cover.
The airline said yesterday that it did not expect any strike-related disruptions during the day.
Strike action was also taken on 22 and 23 August.
Ryanair lost a legal bid to prevent the industrial action last month.
In a statement, it described the latest BALPA strikes as “pointless” given the initial industrial action had caused zero cancellations.
The union says the airline has refused to take part in talks to settle the dispute.
It wants to address issues including pensions, maternity benefits and pay structure.
General secretary Brian Strutton said: “Pilots in Ryanair are seeking the same kind of policies and agreements that exist in other airlines, our demands are not unreasonable.
“Ryanair should stop dragging its feet and get back to the negotiating table.”
The action by UK pilots coincides with planned five-day strikes by Spanish pilots after mediated talks were unsuccessful.
Spanish pilots union SEPLA said it had called on around 900 pilots to walk out on 19, 20, 22, 27 and 29 September.
In July, Ryanair told staff it was planning to cut hundreds of jobs as it had 900 more staff than needed.
Chief executive Michael O’Leary said in a video message: “We will need about 600 less pilots and cabin crew for summer 2020.”
He also said the “increasing likelihood” of a no-deal Brexit had added to the challenges facing the airline.