With the development of next-generation wireless communication and Internet of Things, Vehicular Ad Hoc Network (VANET) has emerged as a cornerstone for enhancing road safety and user experience. However, the performance of VANET is challenged by network partition and barriers, leading to connectivity issues. Unmanned Aerial Vehicle (UAV)-assisted VANET address these limitations by leveraging the high mobility and extended coverage of UAVs, thereby enhancing communication reliability and network coverage. Despite the benefits, UAV-assisted VANET faces security threats due to vulnerable terrestrial vehicles and exposed wireless channels. Although traditional cryptographic algorithms (e.g., key agreement, message authentication codes, and digital signatures) can resist external attacks effectively by authentication and encryption, they have no ability to counter internal attacks. To address the limitations of cryptographic solutions, trust management has emerged as a promising alternative to ensure the security. This chapter outlines the network architecture of UAV-assisted VANET, discusses various attacks, classifies trust management schemes, and highlights unresolved issues.