Question: The Champaign Aviation Museum is an aviation museum in Urbana, Ohio, in which country, the museum and its volunteers are restoring a B-17 Flying Fortress back to flying status, a our-engine heavy bomber developed in the 1930s for the United States Army Air Corps (USAAC)?
Sentence (from "Boeing B-17 Flying Fortress"): From its introduction in 1938, the B-17 Flying Fortress evolved through numerous design advances, becoming the third-most produced bomber of all time, behind the B-24 and the multirole Ju 88.
Relevant evidence: No