I was listening to American Airline’s conference call on Friday, and was struck by a statistic about how poorly the Brazilian economy was doing: Two years ago, when the American Airlines/US Airways merger was approved, the combined airline was generating about 6 percent of its revenue from service to Brazil. Today, it’s more like 2 percent. Soon after the merger, US Airways’ flights to Sao Paulo and Rio de Janeiro — the only flights from North Carolina to South America — were cut. Given the very poor state of Brazil’s economy, it’s uncertain whether the routes could have survived had US Airways remained a stand-alone carrier with no better option than CLT — in the current environment, they would almost certainly been major money losers.