SEPLA has called on around 900 pilots to walk out on Sept. 19, 20, 22, 27 and 29. Some of those dates coincide with planned strikes already announced by the Irish airline's cabin crew in Spain.

The first two days of the cabin crew strike this week forced Ryanair to cancel fewer than one percent of its daily schedule of flights to and from Spain. It also avoided any cancellations during recent strikes in Portugal and Britain.

(Reporting by Conor Humphries, writing by Padraic Halpin, editing by Andrew Heavens)