Argentina has a good air communication. Ezeiza International Airport, located on the outskirts of Buenos Aires, is the most important and the main one in the country.
If you arrive at Ezeiza airport, you can take several buses that take you to Buenos Aires city. The ride is rather long (up to 2 hours if traffic is heavy), but buses are much cheaper than taxis and you avoid the possibility of being cheated by taxi drivers.
There are a countless border crossings, both by land and by water, connecting Argentina with neighboring countries: Uruguay, Brazil, Paraguay, Bolivia and Chile.
To travel from Chile, usually you can do a hike through the Andes, while overland travel to Bolivia, you can go through the cities of La Quiaca, Tarija or Pocitos / Yacuiba. To Paraguay you can go by bus or boat through the river, and the most frequent way to go to Brazil is via Foz do Iguazu or Uruguayana. Uruguay and Argentina are connected by road bridges, and ferries that depart from Buenos Aires to Colonia or Montevideo, Uruguay.