Following a November review of the Mexican civil aviation authority, the U.S. Federal Aviation Administration has upgraded the nation's carriers to a Category 1 rating. The FAA had downgraded Mexico to a Category 2 rating in July, based on the country's inability to meet some international safety standards set by the International Civil Aviation Organization. Since then, Mexican carriers were able to maintain existing routes but weren't permitted to establish new service to the U.S. But in last week's report, the FAA praised the significant progress made by the country's air system since last summer. Mexican carriers are again permitted to add routes and flights.