We got a flight to Puerto Iguazu and 3 days later to Salta. Our travel agent Jackson arranged these for us, including pick ups from the airports and the hotels. It wasn't cheap going this way but it took some of the headaches out of it. I think it's the first time we've had someone standing near the airport exit with our names on a sign.
Unfortunately the flights were early morning but at least we had much of the day after both to wander about the respective towns.
Puerto Iguazu exists largely for the spectacular tourist attraction and natural wonder that is Iguazu Falls. It's also so close to Brazil that many shops and restaurants cater to Brazilians and even price in Reals. That was a bit odd but since we are getting accustomed to pesos we asked for prices in the Argentine currency. You can always pay in US dollars too but we don't.
The hotel was decent, with a pool and buffet breakfast, handy as we had early pickups. The Argentine side of the falls is close, only about a 30 or 40 minute drive.