For Washington-Niagara Falls (United States Of America) flights, you can use Baltimore Washington International (BWI) Thurgood Marshall Airport, Baltimore Greenbelt Airport, Bolling Afb Airport, Buzzards Pt S Airport, Dulles Intl. Airport, Pentagon Army Airport, Ronald Reagan Washington National Airport as departure airport, and Niagara Falls Intl. Airport, Niagara Falls (VIA) station Airport for arrival.