The steady oscillations of elastically fixed thick plates in the air flow are considered. The oscillation amplitudes are measured using the strain gauge method. In experiments, the aspect ratio varies. Some of the experiments were performed with end plates. Steady-state oscillation amplitude increases with an increase in plate aspect ratio. In the presence of end plates, the oscillation amplitude linearly depends on the Strouhal number. Increasing the aspect ratio of the thick plate from 5 to 7 does not lead to a significant change in the amplitude of oscillations.