Frankfurt - Lufthansa chief executive Carsten Spohr was forced to fly with competitor Air Berlin, as his company's strike entered the sixth day on Thursday.
Spohr flew Air Berlin on Wednesday evening from Berlin to Munich, a spokesman told German daily Handelsblatt.
He reportedly thanked the pilots and took his place in row 20.
The somewhat embarrassing news came Thursday as Lufthansa flight attendants once again walked out in a dispute over pay and retirement benefits, leading to the cancellation of 900 flights.
On Thursday, Spohr was able to board one of the few Lufthansa flights from Frankfurt to Berlin as an estimated 107 000 passengers were affected by the longest-running strike in its history.
Spohr joined the company in May 2014, see his welcome address.