Brasília has a large daily influx of sightseers and lobbyists, so the international airport connects with all major Brazilian cities. There are also some direct international connections.
Brasília’s shiny Aeroporto Presidente Juscelino Kubitschek is 12km south of the center.
The easiest way to and from the airport is Ônibus Executivo Aeroporto, which runs from the far right of the arrivals hall (as you arrive) into the center (20 to 40 minutes). It's a good introduction to the city, as it takes you right past most of the iconic buildings before dropping off in the hotel districts. It departs just outside the arrivals hall to the far right as you leave.
Bus 0.102/102.1 runs between the local bus station and the airport for R$3.50 (40 minutes).
Taxis to the airport cost around R$60.
In Brasília, you can book flights through the travel agencies in the Hotel Nacional complex, but airline offices are all at the airport.