ZURICH (Reuters) - Oliver Lackmann, the managing director of insolvent Air Berlin (>> Air Berlin Plc) unit Niki, will leave the airline next month, Austrian media reported on Wednesday.

Austrian Aviation Net posted on its website what it called a letter to staff in which Lackmann said his departure had been planned for months and was unrelated with Niki's insolvency filing.

Niki was not immediately available for comment on the report.

(Reporting by Michael Shields and Silke Koltrowitz in Zurich and Kirsti Knolle in Vienna)