The Prairie Aviation Museum at the Bloomington, Illinois airport has a fully functional DC-3 painted in Ozark Air Lines colors. They fly it to air shows throughout the summer and fall and offer 20-minute rides for $50. I took four flights on it in May at Bloomington -- one of the great thrills of my life! The people are wonderful and the airplane is a dream. For a few dollars extra I got a ride in the jumpseat. The website is www.prairieaviationmuseum.org.
It will have the airshow schedule for the remainder of the fall.
Its the best option I've ever found for riding in a DC-3 in the United States.