As of October, 2015, tour packages in Washington D.C,. that include visits to Smithsonian Museums include walking, bike, Segway and hop-on-hop-off bus tours. Each of these tours includes visits to at least one Smithsonian Museum location, including the National Air and Space and Natural History museums.
Cost and availability of any particular tour vary by season and day. For up-to-date costs and tour options, NationalMallTours.com and Viator.com list tour availability and allow users to reserve tour space. The walking, bike and Segway tours follow designated routes at steady, fixed speeds. Hop-on-hop-off bus tours allow visitors to stay at each site for the duration of their choosing or bypass some altogether.