Dozens of aircraft and spacecraft — including military, commercial and experimental models — are on display at the museum's massive Stephen F. Udvar-Hazy exhibition hangar, 28 miles (45 kilometers) west of Washington D.C. The museum was constructed in 30 months on 176 acres (70 hectares) next to Dulles International Airport.
"The biggest challenge was to create a building worthy of the collection," said Bill Hellmuth, designer of the exhibition hangar.
His company also designed the Air and Space Museum's main facility on the National Mall 25 years ago. That museum, which will remain open, is the most visited museum in the world, drawing 9 million guests in an average year and nearly 11 million in the 12 months ending Sept. 30. The new facility is expected to draw 3.5 million visitors in its first year of operations.
The Virginia site was opened because the original museum only had room to display 10 percent of its collection; another 10 percent has been on loan to museums around the world, and the rest was in storage until the new museum opened.
"This will contain 80 percent of the largest and most completed collection of air and space artifacts," said Gen. John R. Dailey, the museum's director.
"You can get eye to eye with any aircraft in the museum," said Dailey, a retired Marine Corps aviator who flew 450 combat missions in Vietnam. Two catwalks extending up to 44 feet (13.2 meters) above ground level provide up-close views of planes suspended from the rafters.
With 350,000 square feet (31,500 square meters) of hangar space, the $311 million Udvar-Hazy Center houses 82 racers, gliders, helicopters, warplanes and airliners among its 350 major exhibits and displays. Notable are the S-R 71 Blackbird, an American spy plane that still holds the record as the fastest plane ever built; a Concorde, donated by Air France after the fleet of trans-Atlantic luxury jets was retired this year; a Boeing 307 Stratoliner and a Boeing 707; one of Amelia Earhart's flight suits, and a replica of a Wright Brothers' flying machine.
The spacecraft collection includes the space shuttle Enterprise, which was used by NASA to test various concepts during the development of reusable spacecraft, and the Spacelab module. John Glenn, the first American to orbit the Earth, and Neil Armstrong, the first man to walk on the moon, were among the celebrities who gaped at the collection at the museum's opening.
One exhibit has already sparked some controversy: the Boeing B-29 Bomber Enola Gay, which dropped the atomic bomb on Hiroshima, Japan, on Aug. 6, 1945. The Enola Gay exhibit does not note the impact of the plane's famous mission, and the museum's Dec. 15 opening was disrupted by protesters who believe the Smithsonian should display text stating that 230,000 people were killed in the attacks on Hiroshima and a subsequent atomic bombing of Nagasaki. Japan surrendered unconditionally six days after the Nagasaki bombing, ending World War II.
Museum officials omitted the information in order to avoid the controversy that grounded a 1995 exhibit of the Enola Gay that did describe the effects of the atomic bombing.
But most visitors said they were impressed with the new annex.
"Seeing all of these aircraft fully assembled is getting to see history," said Ray Kimball, 30, of Menloe Park, California. The Army helicopter pilot toured the facility with his three year-old son. "I'll have to bring him back when he's older."
The museum's collection also traces the evolution of materials used in aerospace engineering. Aircraft predating World War I are stitched together with canvas and leather covering the wooden frames. The monoplanes and warplanes of the 1930s and '40s include riveted steel. Modern aircraft are made of lightweight aluminum, Fiberglas and composite materials. Uniforms, flight suits and apparel reflect how the men and women who pioneered flight and space exploration dressed to protect themselves from the elements and the ravages of warfare.
The Smithsonian is still seeking other historic aircraft to include in the new museum, including a B-24 bomber. "The Liberator was the most-produced bomber in World War II and we don't have one," Dailey said.
It will take four years to completely restore another 118 aircraft also slated for inclusion in the permanent collection. Many of the planes, helicopters and other aerospace artifacts have been crated away for more than 25 years, said Russell Lee, an aeronautics curator.
Lee said restoration work often provides insight into the people who built or flew the aircraft — like some of the collection's recently restored Japanese warplanes.
"We found graffiti put inside the aircraft by the assembly workers on the line and in every case it's different and unique," he said.
The Smithsonian's aerospace collection also will eventually be displayed in the 53,000-square-foot (4,770-square-meter) James S. McDonnell Space hanger.
The hangar is named for Steven F. Udvar-Hazy, a Hungarian immigrant who made a fortune in aircraft leasing. Udvar-Hazy donated $60 million in 1999 for the project, which is estimated to cost $311 million when complete. At the time it was the Smithsonian's largest-ever donation.
Outside the hangar, visitors can watch planes taking off and landing at Dulles from a 164-foot-high (49.2-meter-high) observation tower. It has equipment like that used in an airport control tower.