Michael O'Leary pens impassioned plea to Ryanair pilots to get them to remain at the airline
He has promised a raft of changes including improved pay and conditions.
In a letter seen by Independent.ie, Mr O'Leary implored his 4,200 pilots not to leave to join airlines such as Norwegian.
"If you have, or are considering joining one of these less financially secure or Brexit-challenged airlines, I urge you to stay with Ryanair for a brighter future for you and your family," he said.
The unprecedented plea comes amid a grassroots movement among Ryanair pilots to unionise in order to seek better employment conditions and pay.
Mr O'Leary also sought to clarify comments he made about pilots following the company's annual general meeting two weeks ago.
He insisted that his comments were "misreported".
The outspoken boss said after the AGM that pilots had an easy job except in adverse weather conditions or during air traffic control strikes.
He said that Ryanair pilots only worked an average of 18 hours a week and that most of the time they could get in an aircraft and hit autopilot and often have little else to do.
"I emphasised (as I always do), that Ryanair's pilots are the best in the business, who work hard, are well trained and extremely professional," he said in today's letter.
"I am proud of your skill and experience, operating across multiple airports, especially during bad weather," the airline chief added.
He claimed that critical comments he made were "specifically directed" at pilots of competitor airlines and their local unions "who take every opportunity to criticise and denigrate Ryanair, our pilots, our safety, our operating performance and our business model despite our collective 30-year success".
Mr O'Leary also included a snapshot of Norwegian's financial performance, claiming the airline is in "trouble".
Norwegian has hired 140 Ryanair pilots since the start of the year.
Mr O'Leary claimed Ryanair pilots will see "significant changes to, and investment in our rostering and pilot career development" over the next six months at the airline.
"Our chief people officer, Eddie Wilson, has now taken direct control of our pilot recruitment and rostering functions," he said.
He said pilots would soon be informed of "significant improvements to your rosters, your pay, your basing, your contracts and your career progression".
He has pledged to benchmark pilot pay against that of 737 pilots in Norwegian and Jet2, and intends to exceed what those airlines pay.
He has also promised other financial measures and signed the letter, "best wishes".
Hundreds of Ryanair pilots have joined unions over the past two weeks following a disastrous rostering failure that saw the airline cancel thousands of flights.
Many of the pilots are unhappy with their employment terms and conditions, as well as pay.