Geoffrey O’Byrne White, the chief executive of Dublin-based airline CityJet, will step down at the end of August. A successor has not yet been appointed and the company’s chairman, Pat Byrne, will act as interim chief executive. Mr O’Byrne White (55) is not retiring, according to a company spokesman, and has “something in the pipeline” but he was “not in a position” to give further details. Mr White was “moving on” after 10 years at the airline.