Comment by silvestrov

Pentagon to Dulles Airport is 20 miles in direct distance.

It takes 1 hour by subway as there is no direct connection and the lines have a lot of stops.

The real solution would be a direct subway with no stop between Dulles and Pentagon. 20 miles using a fast subway should be no more than 25 minutes in travel time. The subway could then continue making a loop in central DC, serving all the offices next to the White House etc.

But that would be good public transportation and that is outside of Congress' Overton Window.