The National Air and Space Museum plans to reimagine and renovate its main hall, Milestones of Flight, for the first time since the museum opened its doors on July 1st, 1976. The Smithsonian seems to think things are starting to look a bit dated, and aims to revamp its central exhibition — which has attracted more than 310 million visitors — with a 21st century look featuring new themes and displays suited to today’s visitors. The Milestones space is currently the museums largest, and its set to grow even bigger;