Apparently this will be the way to fly internationally in 2021. Many countries will require a negative Covid-19 PCR test in order to enter back in the country, and this test is offered at São Paulo Int’l Airport (Guarulhos). The testing capability of the airport was greatly improved last week and it can now run up to 150 thousand tests monthly. According to their website this is the largest airport testing facility in the world.
The facility has 14 testing booths and works 24 hours a day, 7 days a week. It is located at the international sector of the airport.
The test costs BRL 350 (~USD 65), but there are many deals with different airliners and mileage clubs for a discounted rate. The tests have oficial validity with the World Health Organization and are delivered in a max of 4 hours, in english and portuguese.