Virgin Atlantic's chief commercial officer Julie Southern is to depart the airline.
Southern had been seen as the frontrunner to succeed Steve Ridgway as chief executive until Craig Kreeger landed the top job in January.
Southern will leave on 10 May to pursue "new challenges" after 13 years with Virgin Atlantic, the airline confirms.
"She leaves the airline having most recently set up the Delta joint venture deal, and has been pivotal in leading the airline's commercial endeavours during times of rapid growth and expansion," it adds. "She will remain a close friend of the airline and we wish her well."