Airports

From GRA

http://www.metwashairports.com

Dulles airport (IAD)

http://www.metwashairports.com/reagan
Not very far from the outlets : if you give a ride to a friend, few more miles and you are in Leesburg :)

Baltimore airport (BWI)

Reagan airport (DCA)

http://www.metwashairports.com/reagan
This one has the advantage to be in washington DC, so you can go there by metro (the metro station (blue line) is Inside the airport ^_^)