Abstract: With the rapid development of unmanned aerial and underwater vehicles, various tasks, such as biodiversity monitoring, surveying, and mapping, as well as, search and rescue can now be completed in a single medium, either underwater or in the air. By systematically examining the water–air cross-medium locomotion of organisms, there has been growing interest in the development of aerial-aquatic vehicles. The goal of this review is to provide a detailed outline of the design and cross-medium theoretical research of the existing aerial-aquatic vehicles based on the research on the organisms capable of transiting between water and air. Although these designs and theoretical frameworks have been validated in many aerial-aquatic vehicles, there are still many problems that need to be addressed, such as inflexible underwater motion and unstable medium conversion. As a result, supplementation of the existing cross-medium biomimetic research, vehicle design, power selection, and cross-medium theory is urgently required to optimize the key technologies in detail. Therefore, by summarizing the existing designs and theoretical approaches on aerial-aquatic vehicles, including biomimetic research on water–air cross-medium locomotion in nature, different power selections, and cross-medium theoretical research, the relative problems and development trends on aerial-aquatic vehicles were thoroughly explored, providing significant help for the subsequent research process.

Key words: Aerial-aquatic vehicle , · Cross-medium motion , · Power selection , · Control theory , · Biomimetic