Public transportation can be somehow problematic in some North American cities since these metropolitan areas are very spread out and the network itself is not very developed. Such limitations may be in part to the fact that almost everybody drives their own car everywhere they go. On the other hand there are a handful of cities that have a public transportation network as good as any other tourist destination in the world, this is the case of cities such as New York, San Francisco, Chicago and Washington.
The capital of the United States is one of the most visited destinations in the country not only for national tourists but as well for many millions of international visitors, all this has contributed to develop transportation options for the visitors that come here without a car.
There are three main airports serving Washington DC and the other cities around it. Ronald Reagan Airport is commonly referred to as National Airport. This is probably the best for those staying in the downtown and that are coming to visit the main tourist attractions in the city. The only problem is that it offers mostly national flights with some flights to Canada and the Caribbean; the limiting factor is the length of the runway. The airport is accessible by the Metro System, there is a station in the terminal and from there one can access the whole metro system what is very convenient to access almost any point of the city. The first trains depart around 5 am and the last ones around midnight. On Fridays the network operates until around 2 am. The fares are a little different according to the destination but one can expect to pay from 1.50 USD to maximum 5.75 USD
Dulles international airport is the one the gets the most of international flights, it takes at least 40 minutes to get there driving, but it can be even more during rush hours, public transportation options are most limited and these are reduced mostly to private shuttles and taxis. Metrobuses operates a shuttle each hour and it cost 3 USD. Washington Flyer coach service costs 9 USD and departs every half hour from door 4 on the arrivals level.
Baltimore Washington International is a less congested airport and many times it offers better prices than the other two. The Mark trains only run on weekdays from the station there is a free shuttle to the airport. The Amtrak train station is as well located nearby and it makes transportation easy to Union Station in Washington and beyond including Philadelphia, Virginia and even New York City. There are free shuttles running from the airport to the station, these shuttles stop between doors 1 and 2, 8 and 9, 14 and 15. There is as well a shuttle running every 40 minutes from the airport to the Greenbelt Metro Station and from there it is possible to access the whole Metro Network and all its destinations.