There are two airlines flying to Iguazu Falls from Buenos Aires: LAN and Aerolineas Argentinas.
According to our experience, one is not better than the other so feel free to choose the one you like.

The flight is 90 minutes long and you will be leaving from the domestic airport located inside the city of Buenos Aires. You are required to be at the airport one hour in advance. From most hotels in the city you will need 20 minutes to get to the airport.

Flight schedule varies according to season, but there are around eight flights a day. Flights run out of seats pretty fast so we recommend to book as early as possible.