An aircraft (10) or other conductive body having an electrical conductor which is capable of storing electrical charge, the aircraft comprising: connection means (20, 22, 24) for connecting said conductor with at least one other aircraft (10) having an electrical conductor capable of storing electrical charge so that stored charge can be transferred to and/or received from said at least one other aircraft; and control means (32, 34) for controlling transmission of charge so as to convey information to said at least one other aircraft and/or information extraction means (32, 34) for extracting information from the transmission of charge received from said at least one other aircraft.