The rapid advancement of Mobility-as-a-Service (MaaS) within the transport sector has brought forth critical challenges in safeguarding privacy and ensuring data security for its participants. In response, blockchain technology has emerged as a promising solution, offering a decentralized and tamper-resistant infrastructure. This survey paper aims to present a comprehensive overview of the utilization of blockchain in the transport sector, with a specific focus on MaaS, and explores its potential role in preserving privacy and enhancing security. We delve into the privacy concerns related to data collection, sharing, and storage within MaaS systems, and examine how blockchain can address these issues through its unique characteristics of transparency, immutability, and cryptographic techniques. By conducting an extensive survey, we analyze the existing blockchain-based privacy-preserving mechanisms applied in the transport sector, shedding light on their efficacy, limitations, and potential applications. Through this survey, we aim to provide valuable insights to researchers, practitioners, and policymakers, highlighting the potential of blockchain-based privacy-preserving approaches in constructing secure and efficient MaaS ecosystems within the context of the Internet of Vehicles (IoV). The study emphasizes the significance of blockchain technology in safeguarding the privacy of participants' data and enhancing overall security, paving the way for the future of privacy-conscious and robust MaaS platforms in the dynamic transport sector. Index Words: Blockchain, Blockchain-based, MaaS, Privacy, Mobility-as-a-Service, Transport-Sector, Security, IoV, Internet of Vehicles.