Experimental evidence suggests that vortex breakdown is not the only source of buffeting of delta wings and fins. Other unsteady flow phenomena that contribute to buffeting at high angles of attack are fluctuations of vortex breakdown location and vortex shedding. Flow visualization and velocity measurements were carried out over a delta wing, over a wide range of angles of attack, to understand the transition between the helical mode instability and the vortex shedding. It was found that this transition is abrupt, as indicated by a jump in the frequency parameter, and that it occurs at the angle of attack at which breakdown reached the apex. The unsteady nature of vortex breakdown location was investigated by flow visualization for the interaction of vortex breakdown with a rigid flat plate. Although there are indications of a feedback effect on vortex breakdown, the amplitude of the fluctuations of breakdown location is smaller for impinging flows