The U.S. government is preparing to downgrade Mexico's aviation safety rating, a move that would bar Mexican carriers from adding new U.S. flights and limit airlines' ability to carry out marketing agreements, Reuters reported. The Federal Aviation Administration's (FAA) planned move is expected be announced in the coming days and follows a lengthy review of Mexico's aviation oversight by the agency. One airline industry source said the FAA's concerns did not involve flight safety issues but rather Mexico's oversight of air carriers. Downgrading Mexico from Category 1 to Category 2 would mean that current U.S. service by Mexican carriers would be unaffected, but they could not launch new flights and airline-to-airline marketing practices such as selling seats on each other's flights in code-share arrangements would be restricted. The action would mean that the FAA has determined that Mexico does not meet International Civil Aviation Organization (ICAO) safety standards as part of its safety assessment program. Read more.