Aeropuerto Internacional Ezeiza in Buenos Aires is the main point of entry, and there are frequent bus services into the city. Taxis are more expensive, but it is wise to agree a price in advance before getting one, and few of the drivers speak English.
It is possible to fly between most of the cities in Argentina, but one of the best ways to see the country is to use one of the high-speed long distance buses that are available. Roads are good, and there is plenty of scenery to watch as you travel.