PARIS (Reuters) - Two of the top executives in European planemaker Airbus <AIR.PA> have written to institutional investors in a display of unity over the future of the A380, in a move to ease concerns that it may be canceled, two people familiar with the letter said.

Harald Wilhelm, finance director of both Airbus Group and its planemaking subsidiary, and sales chief John Leahy jointly signed the letter, which said no senior executive had contemplated axing the world's largest airliner.

Airbus Group and the Airbus jetmaking unit declined comment.

Speculation over the plane's future flared up last month when Wilhelm, in a discussion about the robustness of his financial forecasts, told analysts that the A380 would break even through 2018, even if Airbus decided to discontinue it.

Besides raising questions over the aircraft itself, several analysts said the comments had revived the issue of divisions between the planemaking unit and the parent group.

Such in-fighting hampered the development of what was then known as EADS during the middle of last decade. But the company has said these problems are in the past following changes in management and corporate governance.

Fabrice Bregier, head of the planemaking division, said this month that the best days of the A380 were ahead and denied any divisions inside the Franco-German-led group.

Airbus has struggled to win sales for the 525-seat jet recently, but Turkish Airlines <THYAO.IS> is in negotiations to obtain 10 or more A380s in a deal potentially worth $4 billion, two people familiar with the matter said earlier this week.

The aircraft could be supplied through a combination of direct purchases and leasing, but Airbus is likely to face intense competition from rival Boeing <BA.N>.

(Reporting by Tim Hepher. Editing by Jane Merriman)