Bus Travel -- not what it used to be

[DisneyOma]

Actually both BOS and DCA are located very close to downtown.

BOS is just a Big Dig from downtown Boston, and DCA is in Alexandria, VA, and both have Metro routes running frequently right into downtown. People can, and do, ride Metro to both downtown areas from the airports.

In Washington, Dulles is somewhat farther out -- but Union Station is directly downtown, just across the street from the US Capitol.

"Just a Big Dig from" is a pain in the butt though - traveling from north of Boston, you can get into North Station easily enough by train, but getting over to South Station isn't a direct route on the T.