Brazil's airports will probably manage to handle the massive traffic to the 12 World Cup host cities even though some upgrades are behind schedule, ratings agency Fitch said Monday.
The country's airports are expecting to receive 3.7 million passengers, including 600,000 foreigners, during the June 12 to July 13 tournament.
"As Brazil's railway network is limited, airport infrastructure will be critical," said Fitch.
Since 2003, passenger traffic has leapt from 33 million to 111 million a year, according to Brazilian figures, an increase that has strained the aging airport infrastructure and caused chronic delays.
Officials say 5.6 billion reais ($2.5 billion, 1.9 billion euros) has been spent upgrading the airports -- mainly to get passenger terminals, airplane ramps and runways ready for the World Cup rush.
Of the 10 host city airports run by aviation authority Infraero, the ones most at risk of missing the World Cup deadline are Cuiaba, which is hosting four matches, and Fortaleza and Belo Horizonte, which are each hosting six, said Fitch.
"The Cuiaba airport presents the most challenging situation, with only 75 percent of scheduled works completed, while Fortaleza will operate through temporary structures," it said.
Privately run airports in capital Brasilia and economic hub Sao Paulo are also still under construction, at a total investment of $1.8 billion.
President Dilma Rousseff, who is up for reelection in October, repeated Monday that the upgraded airports would be a "legacy" of the World Cup, whose $11-billion price tag has sparked protests in a country with critical needs in education, health care and transport.
She said the airports "are ready for the World Cup" in her weekly "Coffee with the President" radio program.
In Rio, the main airport's capacity has been increased by 80 percent, she said, adding more upgrades would be undertaken between the World Cup and the 2016 Olympics in the city.
She said the government was also investing $7.3 billion reais on expanding 270 airports in the interior of the massive South American country.
Rousseff will travel to Sao Paulo Tuesday for the inauguration of the main airport's new terminal, which will have a capacity of 12 million passengers a year.