So as to reduce its size, the invention provides a multistage ejector for generating a vacuum across a first, drive stage comprising a drive nozzle array for generating drive flow of air from a compressed air source, the drive nozzle array including two or more nozzles arranged to feed respective air jets together substantially directly into a common outlet of the drive stage so as to entrain air in a volume surrounding the air jets into the drive flow in order to generate a vacuum across the drive stage, the outlet of the drive stage being the inlet of a converging-diverging nozzle of a second stage, the converging-diverging nozzle being arranged to direct said air as a second stage air j et substantially directly into an outlet of the second stage so as to entrain air in a volume surrounding the second stage air jet into the flow in order to generate a vacuum across the second stage.