Ryanair pilots have agreed to go on strike for seven days this month.
The pilots are set for more industrial action, after walk outs on August 22, August 23 and earlier this week, in a dispute over a range of issues including pay, pensions and maternity benefits.
Members of the British Airline Pilots Association (Balpa) announced they will strike again in mid and late September.
Pilots will strike for 48 hours on September 18-19, before 24 hour walk outs on September 21, 23, 25, 27 and 29, unless the dispute is resolved.
Ryanair flies from Newcastle Airport , Edinburgh Airport and Leeds Bradford Airport, among others.
The union says Ryanair is refusing to take part in talks with Acas to settle the dispute.
General secretary Brian Strutton said: "We are clear that we want to settle the dispute and bring about a change in Ryanair for the better.
"Pilots in Ryanair are seeking the same kind of policies and agreements that exist in other airlines, our demands are not unreasonable.
"We want to address issues like pensions, loss of licence insurance, maternity benefits, allowances and harmonise pay across the UK in a fair, transparent, and consistent structure.
"While this action has considerably disrupted Ryanair, forcing them to engage contractors and bring in foreign crews to run its operation, it has had limited impact on the public's travel plans.
"Ryanair should stop dragging its feet and get back to the negotiating table."
A Ryanair spokesman said: "These latest strikes are pointless given that during five days of strikes (August 22-23 and September 2-4) all Ryanair flights to and from UK airports operated as scheduled - with zero cancellations - thanks to the efforts of over 95% of our UK pilots who flew as rostered and did not support these failed Balpa strikes.
"We again call on Balpa to return to talks as these failed strikes have not achieved anything."
