As part of the merger between Tui Travel and Tui AG, Long was slated to move upstairs with Friedrich Joussen becoming sole chief executive.
However, in a statement Tui said that Long will instead become just a member of the supervisory board.
Klaus Mangold the current chairman will remain in the role.
A spokesperson for Tui told TTG that the reason for the change of heart was corporate governance regulations in the UK and Germany.
“The supervisory board of Tui AG has laid the groundwork for a long-term management structure. Under the leadership of Fritz Joussen, the management board will continue on its successful course and remain committed to the implementation of the initiated strategy”, Mangold said.
Meanwhile, Tui also brought forward the release of its pre-close trading update.
The firm described summer 2015 trading as “robust” with a particularly strong performance in the UK market.
Bookings are up 1% and average selling prices are up by 2%.
Analysts had suggested the likes of Tui and fellow tour operator Thomas Cook would benefit from the wet weather in the UK this summer.
Trading for winter 2015-16 is in line with the company’s expectations. Bookings are flat and average selling prices up 4%.
Tui also said trading for summer 2016 had got off to a strong start in the UK with bookings up 8%.
The company is sticking to its full-year guidance of underlying operating profit growth of 12.5% to 15%.