Brazilian airlines, including heavyweights TAM and Gol, have asked the country's aviation authorities to allow some 1,500 additional flights to meet demand during the World Cup, officials said on Wednesday.
A statement from the National Civil Aviation Agency (ANAC) said the airlines' requests were being considered and "will be approved based on the capacity of each airport" in terms of runways and parking space.
ANAC said it would publish its final decision on January 15.
Brazil hopes to welcome 600,000 foreign visitors during the World Cup, which is also expected to draw three million Brazilians.
There is no real alternative to air travel in this continent-sized country of more than 200 million people, where airports often are congested and in urgent need of an upgrade.
Authorities have launched an airport modernization drive, but it will be completed only in 2018.
Brazil's poor airport infrastructure limits the prospects for increasing the number of flights during the tournament, which will be held in a dozen host cities across the nation from June 12 to July 13.
ANAC will have to schedule part of the new domestic routes at alternative hours, taking into account the match schedules.
"We will try to accommodate everybody based on the structure of the 25 airports concerned," the O Globo daily quoted Moreira Franco, head of the Civil Aviation Secretariat, as saying.
The top five routes preferred by the airlines are Brasilia-Sao Paulo (Guarulhos airport); Rio de Janeiro-Buenos Aires, Rio de Janeiro-Campinas (in Sao Paulo state), Fortaleza-Sao Paulo and Salvador-Sao Paulo.
The airlines are pushing for a 48 percent increase in the number of flights in Cuiaba, capital of the central-western state of Mato Grosso.
They also want 36.5 percent more flights at Sao Paulo's Guarulhos airport, 27.5 percent more in Natal, 17.8 percent in Fortaleza, 14 percent more in Salvador and 13 percent more in Recide and Rio, according to ANAC.