The propagation of electrostatic plasma wave energy in the auroral E region has been studied using fluid theory. Typically, a wave travels at higher speed nearly parallel to the magnetic field, except possibly for a small height interval where it is reflected upward; throughout, the direction of the propagation vector remains virtually unchanged and nearly perpendicular to the magnetic field. If k makes an angle of more than 0.25¿ with the magnetic field, the wave passes through the E region without reflection. Kinks in the magnetic field lines (due to auroral currents) may lead to trapping of waves in layers less than 1 km thick. Secondary irregularities may be limited in both horizontal and vertical extent because of their motion relative to the primary waves on which they depend on growth. The processes determining the amplitude of irregularities have also been considered in the light of this work. Several observed features of radio aurora may have explanations in terms of these properties of energy propagation.