A wearable device that is wearable by a user and connectable with one or more aircraft related systems, a device system comprising a plurality of such wearable devices, and an aircraft comprising such a device system. The wearable device that is connectable to one or more aircraft related systems comprises a system interface via which the wearable device is connectable to one or more aircraft related systems, and a control unit configured to communicate with at least one of the one or more aircraft related systems via the system interface.