Lightweight authentication and key agreement play a key role on the Internet of Drones. In this note, we show that the Zhang et al.'s lightweight authentication and key agreement scheme [Computer Communications, 2020 (154), 455-464] for the Internet of Drones is not truly anonymous because it has confused the differences between a public key and public parameters. Instead, it is just a key transfer scheme in disguise and can be greatly simplified due to the presence of a fully trusted Control Server.