There are several flights a day to/from Iguazu falls - BA.
From the airport you can take a taxi or better a rented car with driver (called here "remis") and go direct to the National park to see the falls.
If you have tiem, cros with the remis to Brasil (no visa needed if you only go to the National Park, and you will see the better view. because we have most falls in Argentina, but Brasil have the landscape!!
Brasilian visit can be done in 3 hours.
Argentine vist... it depends of your interest, because you can walk many hours, some path goes till the same border of the main falls.
regards