If you are interested in aeronautics and space exploration, then you cannot miss the Smithsonian National Air And Space Museum.
You will find the museum’s primary building, in DC’s National Mall, displaying nearly 60 aircraft, 50 larger items from humanity’s travel and exploration in space, and over 2000 smaller items. You can also see here the museum inhousing well known artifacts like the 1903 Wright Flyer, Charles Lindbergh’s Spirit Of Saint Lewis, and even SpaceShipOne along with the promptbuscharters.com
You can also visit the Museum’s additional location- The Steven F. Udvar-Hazy Center, being situated next to the Washington Dulles International Airport, 30 miles from the main Air And Space Museum. You will find the Udvar-Hazy Center as having nearly 170 aircraft, and 150 space artifacts on display, composing of the Space Shuttle Discovery. You can explore here the observation tower, and just get the fine view of the air traffic at the Dulles Airport.
Both Air & Space museums have free admission, and are open 10:00 am – 5:30 pm every day of the year, save for the 25th of December.