public void Deserialize(MemoryStream ms)
                {
                    bool has_flightplan; ms.ReadBool(out has_flightplan);

                    if (has_flightplan)
                    {
                        flightplan = new Flightplan();
                        flightplan.Deserialize(ms);
                    }
                    ms.ReadInt(out prev);
                    ms.ReadInt(out next);
                    ms.ReadInt(out active_waypoint);
                }