Sitting in his office overlooking O’Connell Street, Dublin Bus chief executive Billy Hann reflects on some of the major challenges for the organisation since he took the reins nearly a year and a half ago. Hann, who spent 28 years at the Irish Aviation Authority, was appointed chief executive of Dublin Bus in December 2022. It was at a time when the country was putting the dark days of Covid lockdowns firmly in the rearview mirror while other challenges like climate action and the city’s infrastructure were put firmly back on top of the agenda. With much of Dublin back…