Both American Airlines and US Airways have filed applications to boost service to Brazil ahead of their proposed merger. Last week American applied with the U.S. Department of Transportation to fly more routes to the South American destination. Pending approval, the carrier will offer daily roundtrip service between Los Angeles and Sao Paulo beginning late this year, and between Chicago and Sao Paulo in late 2014. This week U.S. Airways followed suit, applying to offer Charlotte-Sao Paulo service as well as flights between Philadelphia and Sao Paulo. American intends to expand service to Mexico as well, beginning June 12 with new flights between Dallas/Fort Worth and Hermosillo, and DFW and Zacatecas.