Ryanair chief operating officer Michael Hickey has become the first executive casualty at the carrier as it continues to battle the fallout from thousands of cancellations announced last month.
He will step down from Europe’s biggest low-cost carrier at the end of the month.
Ryanair has been forced to cancel more than 20,000 flights over the coming months after a rostering error left it short of pilots.
A search to identify and recruit a successor is underway.
Mistakes meant more than 700,000 passengers have seen flights affected.
At the same time, Ryanair has been forced to scale back growth plans for 2018 by around six million passengers.
Ryanair chief executive Michael O’Leary has taken much of the responsibility.
He said: “Over the past 30 years Mick Hickey has made an enormous contribution to Ryanair.
“He will be a hard act to replace, which is why we are grateful he has agreed to continue in an advisory role to smooth the transition to a successor.”
The operating chief, who assumed the post in 2014, has been at the airline since 1988, joining as an engineer and rising to direct the department.
Hickey will conclude “a number of large projects” before leaving, such as arranging an engine maintenance contract and new hangars in Madrid and Seville, Spain, O’Leary said.