Abstract <p>Among a variety of drag reducing techniques in high-speed vehicles, the use of aerospike is the most simple and reliable one. Unfortunately, this technique has a disadvantage that needs serious consideration. On one hand, a spike mounted on the high-speed blunt bodies reduces drag to a considerable amount. While on the other hand, the spike of a certain length tends to make the flow around the body unsteady thereby raising the possibility of structural failure or loss in maneuverability. There have been a number of studies devoting towards the flow unsteadiness arising due to the implementation of aerospike in recent past. Since the early 1950s, numerical simulation methods as well as experimental equipment have been used to conduct considerable investigation of this unsteadiness over high-speed spiked vehicles. In this study, the survey of these investigations is covered, and the recent contributions of the first author to the present field are shown. In addition to that, several areas of the science that require more research are also highlighted.</p>