For those who visit Brazil and first spend time in Sao Paulo then go to Rio, you might want to be aware of the below article. 

The article advises that the largest runway at Rio's at Santos Dumont airport will be closed for a month for upgrading.  Only small aircraft will be allowed to use the smaller runway at the downtown airport.

This mean that flights from downtown Congonhas Airport (Sao Paulo) will fly to the larger international airport (GIG) in Rio, much farther than downtown Rio (SDU).  

If you are visiting Sao Paulo during the above dates shown in the title, and if you plan to visit Rio from Sao Paulo, make sure you book one of the smaller aircraft to Rio (SDU).  If you don't, your flight will land at Galeão International Airport (GIG) which is a long taxi or Uber ride from the areas we generally use.  Traffic is usually heavy along this route. 

Here is the article:

https://riotimesonline.com/brazil-news/rio-de-janeiro/runway-renovation-will-restrict-flights-at-santos-dumont-airport-in-rio/