Before we came to DC, this was the top of my list to visit, mainly for the Wright Flyer and for the Apollo 11 command module. In the end, the command module was terribly disappointing as it is shrouded in thick plastic and this completely detaches you emotionally from the object.
The Wright Flyer is exceptionally well exhibited, however. You can see every detail and the plane is surrounded by outstanding information about the Wrights' aeronautical engineering. This and the objects donated by individual Astronauts from the Apollo programme stood out, but they were the only things we enjoyed in what was overall an over-curated museum.