Want to be a world power? Then an aircraft carrier, it seems, is the minimum requirement for joining this elite club. You need a blue water navy (deep sea faring navy) to qualify. Currently I would say the US is the only true global naval power. In China, a retro-fitted former Ukrainian carrier dating back to the Soviet era is the flagship of the country's hopes for a "blue water" navy -- a fleet that can operate on the high seas thousands of nautical miles from base. India has launched its first home built aircraft carrier as part of a plan to operate three carrier battle groups by 2020. And Japan -- whose navy is officially classed as a self-defense force -- has controversially unveiled what it has classed as a flat-topped helicopter destroyer, but to China looks perilously akin to an aircraft carrier.