National Air and Space Museum, Smithsonian Institution | 8,880 followers on LinkedIn. The Smithsonian's National Air and Space Museum maintains the world's largest and most significant collection of aviation and space artifacts, encompassing all aspects of human flight, as well as related works of art and archival materials. It operates two landmark facilities that, together, welcome more than eight million visitors a year, making it the most visited museum in the country. It also is home to the Center for Earth and Planetary Studies.