The goal of this systematic review is to examine the use of Brain-Computer Interfaces (BCIs) for controlling unmanned aerial vehicles (UAVs) in real-time. A comprehensive search across various online databases, including IEEE Explore, ScienceDirect, MDPI and PubMed, using the PRISMA research method, was conducted. The total of 42 experimental studies were identified, analyzed, and included in the final report. The review highlights several important research directions and areas that require further investigation in the field. Additionally, it identifies potential future possibilities and trends in BCI-controlled UAVs. Lastly, the review outlines the future challenges that researchers are likely to encounter, aiming to provide valuable insights and guidance for future studies in this area. To the authors' best knowledge, this systematic review represents the most extensive analysis in literature, both in terms of the number of studies included and the span of years considered.