Howard Millar and two other executives are leaving Irish- and US-based aviation leasing specialist Stellwagen Group in a surprise move.
Mr Millar, Ryanair's former chief financial officer, last year joined Stellwagen as chief operating officer and as as chief executive of one of its divisions, Stellwagen Capital.
It emerged on Friday that he and Edward Coughlan and Edward Hansom, two executives of its aircraft leasing and trading arm, Seraph Aviation Management, are leaving the organisation.
None of the three would comment, but it is understood that they are departing as they are unhappy with the group’s strategic direction.
Scott Corman, who joined Stellwagen when it bought ECN Capital's aviation business earlier this year, will replace Mr Millar as chief executive of Stellwagen Capital.
David Butler, who held several roles with Denis O'Brien's telecoms network, Digicel, will take over as Stellwagen Group's chief operating officer.
Based in Stamford Connecticut, Stellwagen Capital will focus on raising cash to finance aircraft purchases.
Mr Millar is one of the Irish aviation industry's best know figures. As Ryanair chief financial officer, he helped oversee its stock market launch, led its first bond issue and negotiated aircraft purchases. He is a non-executive member of the airline's board.
Edward Hansom was chief risk officer with Stellwagen Capital and Seraph and previously worked with GPA. Edward Coughlan was Seraph's chief commercial officer and had worked for Shannon Aerospace.
Founded by businessman, Doug Brennan, Stellwagen is focused on providing finance aircraft, shipping and defence infrastructure. It has $1.7 billion under mangement.
One of its aims is to attract more mainstream investors, such as pension funds, to aircraft finance. Canadian group Acasta bought Stellwagen last year for $270 million.