Machu Picchu and Buenos Aires
 

My husband and I are anticipating a trip to South America and would like to visit both Machu Picchu and Buenos Aires during the same trip. Is there a flight from BA to Cusco? Could we possibly do this trip in less than 9 days?
Thank you for the advice.

You'd need to connect in Lima.

You could possibly do teh trip in 9 days (although it would be a rush)but if you are thinking of trekking the Inca Trail to MP, then no. You would need four days for the trek plus a couple of days to aclimatise to the altitude beforehand leaving just 2/3 days for BA which deserves more.

With only 9 days, my advice would be to plan EVERYTHING meticulously beforehand so you don't waste a second as there is a lot to see in both places

It would be very rushed to see them both in 9 days, but doable. U would need to fly to Lima from BA and get a flight from Lima to Cusco.

Absolutely! In Buenos Aires, you need about 3 days. Do a day tour, a night out at a tango place (Sabor a tango has a lesson before the dinner show), cheap tango lessons at Confiteria Ideal (if you go, please say hi to Eduardo Saucedo and Gabriel from Gabriela Rojo's student Danielle from Vancouver), and if you have a Friday night, go to the biggest dance party anywhere - La Estrella/La Viruta in the Armenian Cultural Centre in Palermo. They have 4 floors of dancing - bottom is easy salsa lessons, 2nd floor is freestyle salsa dancing, then 3rd and 4th floors are multiple levels of tango lessons. I stayed at the Hotel Promenade, Marcelo T de Alvear 444, which is a cheap hotel, a short taxi ride to anywhere or you can walk. It's right next door to an Irish bar full of expat businesspeople on weeknights.
I flew BA-Punta Arenas-Antarctica-Punta Arenas-Santiago-Lima-Puerto Maldonado (Amazon)-Cuzco then went overland to Bolivia, but you can go BA-Lima probably, then to Cuzco. You can visit Machu Picchu by train in a day or two, but if you want to do the hike, you need about 5 days. If you just take the train, do the Sacred Valley for 2 days, it's lovely and worth it to see the countryside and little towns and markets.