CHARLOTTE, N.C. -- US Airways (LCC) says it will begin nonstop service between Charlotte and Rio de Janeiro this fall.The U.S. Transportation Department tentatively said Friday it has tentatively awarded the route. The flight will originate in Philadelphia and will be operated with a Boeing 767 seating 204 passengers. In 2008, Charlotte/Douglas International Airport was the ninth busiest U.S. airport with 34.3 million passengers, according to Bureau of Transportation Statistics. The airport, which is the largest hub for US Airways, was the fastest-growing among the top 10 U.S. airports, with a 4.1% growth rate, which improved its ranking from 14th in 2007. Atlanta's airport, a hub for both Delta ( DAL) and AirTran ( AAI), remains the nation's busiest, with 86 million passengers after it grew by 1.2%. But traffic diminished at six of the 10 largest airports.