According to a new report by the Government Accountability Office, the proposed merger between American Airlines and US Airways is set to reduce the level of competition at a large number of airports in the country.

The report said that the merger would reduce competition in more number of airports than any merger before. It was found that about 1,665 routes between cities will have one lesser competitor following the merger and affect more than 53 million passengers and a new player will be created in 210 routes impacting 210 routes.

The report also said that most of the market will still have effective competitors. It also said that 1,114 routes between cities lost one competitor during the merger of United and Continental. American and US Air have claimed that the merger would only impact a few number of airports as they overlap on only 12 nonstop routes. On the other hand, the report by GOA also considers connecting routs with one stop.

Doug Parker, the chairman and chief executive of US Air said, "The network is able to provide these choices and services because it aggregates demand that independently cannot support profitable service, but collectively can do so." The officials of the two airlines have defended the benefits of the merger before the congress.

The proposed merger would create the leading passenger airline and comes after significant combinations including the mergers of United and Continental in 2010, Delta Air Lines and Northwest in 2008, and Southwest Airlines with AirTran in 2011.