An flight-safe indicator for a battery displays the flight-safety state of a battery to be transported by an aircraft. The indicator can be easily recognized by ground personnel anywhere regardless of the language they speak or read. The indicator comprises an icon indicating that the battery is safe for flight and would be easily recognized by personnel at an airport. The icon would be placed on the battery or on the battery packaging prior to loading on the aircraft. When the magnitude of power stored on the battery exceeds a safety threshold, the icon changes to an indication that the battery is not safe for transporting by aircraft and the operator may discharge the battery using a load until it reaches a safe level.