Holden oversaw Uber Elevate, the company’s flying car operation, which is now headed by Eric Allison but no one in the company is saying why he is leaving.  He is the latest of top execs to flee the company. Uber’s chief legal officer, Salle Yoo, and head of external affairs Dave Clark left the company in September. Uber is also searching for a chief financial officer who can help take the company public in 2019. The CFO position has been vacant since 2015.

New Chief Executive Officer Dara Khosrowshahi has been shaking up the company since taking over Last August aiming to improve Uber’s reputation after a string of scandals.

Uber, along with Lyft scrapped mandatory arbitration to settle sexual harassment or assault claims earlier this week, giving victims several options to pursue their claims including public lawsuits.

Uber launched a new app for its drivers last month, as it tries to improve an often contentious relationship with them.