Former Google CEO Eric Schmidt.Shahar Azran/Getty ImagesEric Schmidt says drones are the future of warfare, calling tanks "useless.""A $5,000 drone can destroy a $5 million tank," he said.Schmidt has a startup building AI-powered drones to help Ukraine.Former Google CEO Eric Schmidt said future wars would be fought by AI-powered drones and urged the US military to do away with what he called "useless" tanks.Speaking Wednesday at the Future Investment Initiative conference in Saudi Arabia, Schmidt said the low cost of automated drones would soon make traditional forms of combat obsolete."The world has an awful lot of tanks.