SPRINGFIELD, Ill.—Chicago-based aerospace giant Boeing Co. will invest $200 million to begin manufacturing the U.S. Navy’s latest unmanned aircraft at MidAmerica St. Louis Airport in a project that could add more than 150 jobs on the company’s southwest Illinois campus, according to an announcement scheduled for Friday. Boeing plans to build the MQ-25 Stingray, the Navy’s first carrier-based unmanned aircraft in a state-of-the-art plant of about 291,000 square feet (27,034 square meters), according to a news release provided in advance to The Associated Press. State and company officials have planned a Friday afternoon news conference to announce the plan at MidAmerica in Mascoutah, about 29 miles (47 kilometers) southeast of St. Louis. “That the world’s largest aerospace company would double-down on Illinois is a testament to our unparalleled assets in the transportation and logistics sector and the world-class talent of our people,” Illinois Gov. J.B. Pritzker said in a prepared …