The ejectors are developed and used for gas turbine engines, to generate effective exhaust noise attenuation without losing engine thrust, but even if possible with thrust increase. Also ejectors are used for subsonic rocket propelled vehicles as thrust augmenting devices, as result of increasing their propulsive efficiency. In this paper, a combined numerical and experimental study is conducted to establish an optimum design of compressible subsonic air ejector as a thrust augmentor and noise attenuator. The theoretical solution of the flow through the exhaust system with ejectors is done numerically by using "Fluent 6.1" package. The package solved the steady 2-D compressible viscous flow by using the finite volume technique. While the experimental measurement of the flow field of the considered problem is done by using Particle Image Velocimetry (PIV) technique. The obtained results help to understand the flow behavior and the physical phenomena occurring in the flow through ejectors, and give optimum design of exhaust ejector to give optimum thrust augmentation and optimum design to give optimum noise attenuation.