Planes of satellites are observed in the Milky Way and Andromeda, and recent observations claim their presence as well in other nearby galactic systems. Moreover, recent proper motion data of MW satellites allege an important fraction of satellites are co-orbiting within the plane they define. However, the quality and degree of co-orbitation of the planes of satellites reported so far from simulations within a ?CDM context have been insufficient to explain the observational data. In order to further understand the origin of planes of satellites we have carried out a detailed study of planes of satellites in zoom-in cosmological hydro-simulations of disc galaxies, focusing on plane-finding methods and plane quality analyses. We report on a method to identify kinematically-coherent satellites based on their orbital angular momentum vectors. We find a group of co-orbiting satellites in the PDEVA-5004 simulation that forms a persistent planar structure across cosmic time, with characteristics compatible with those of the observed planes in the MW and M31.