Since its opening, the National Air and Space Museum's building on the National Mall has been limited by size to the display of only a small fraction of the collection of aircraft and large space artifacts. Thousands of artifacts were forced to remain in storage.

In 1977, Don Lopez, then Chair of the Aeronautics Division, sent a memo to Director Michael Collins, suggesting that massive buildings, much larger than the new Museum, be procured at one of the regional airport facilities. He recognized that modern aircraft were generally larger, heavier, and more difficult to move by road from one location to another. Future acquisitions, perhaps as large as a Boeing 747, would require covered display space and would need to travel there without being disassembled, trucked over miles of highway and then reassembled. Such costs would be prohibitive except in the rarest of cases. Lopez ruled out any location more than one hour's drive from the National Mall in Washington, DC. This criterion narrowed the possibilities significantly.

In 1980, Lopez and Deputy Director Mel Zisfein initiated a study to select the best candidate for the Annex. Dulles Airport seemed most logical, and after some perseverance, the Smithsonian Board of Regents endorsed the plan, and the Federal Aviation Administration offered 100 acres of land to the south of the airport for the construction of the Dulles Annex, but that was just the beginning. 

In 1993, President Bill Clinton signed a law establishing an extension for the Museum at Washington Dulles International Airport in Virginia.