Military defense companies and startups gather at a massive 200,000-acre base in Grayling, Michigan, to test cutting-edge drone technology designed for modern w

Military defense companies and startups gather at a massive 200,000-acre base in Grayling, Michigan, to test cutting-edge drone technology designed for modern warfare. With 7,000 troops carrying out exercises with aquatic and aerial attack drones, tech innovators say Michigan's storied automotive h…