An ejector has a primary inlet, a secondary inlet, and an outlet. A primary flowpath extends from the primary inlet to the outlet and a secondary flowpath extends from the secondary inlet to the outlet, merging with the primary flowpath. A motive nozzle surrounds the primary flowpath upstream of a junction with the secondary flowpath. The motive nozzle has a throat and an exit. In one group of embodiments, an effective area of the exit is variable. In others, the needle may extend downstream from a flow control portion or may have an upstream convergent surface of a flow control portion.