This comes despite the Brazilian Civil Aviation Authority authorizing airlines to operate nearly 2,000 additional flights during the tournament this summer.
The 2014 World Cup will see 12 Brazilian cities host matches, and 600,000 foreign visitors are expected to make the trip.
John Grant, executive vice-president, OAG, says: “Our analytics show that Brazil’s domestic seat capacity is currently down 0.5% in June and 3% in July respectively, compared to the same months last year.
“While this is consistent with Brazil’s trend to cut capacity, 0.6m overseas visitors are reported to be travelling to the games, including 22,000 England fans.
“With the group stages of the World Cup spread between 12 cities across the country, fans will need to travel huge distances to attend the group stage matches and air travel, in most cases, is the only realistic option – Rio to Manaus, where England will play their first match, is a drive of 1,768 miles.
“There are currently just less than 27,000 scheduled aircraft seats in March 2014 between the two cities, making it hard to believe that additional air capacity will not be needed in June.”
According to OAG, Brazil has a well-developed domestic air network, the fourth largest in the world after the USA, China and Japan, including the world’s second largest domestic low-cost carrier network.
In March 2014, there will be 10.5m domestic seats available in Brazil. However, Brazil’s domestic market has recently been softening as the economy has slowed.
As a consequence, carriers have reigned in capacity. Just 12 months ago, in March 2013, seat capacity was 11% higher than March 2014, at 11.8m seats.