Michigan had joined six other states in a US antitrust lawsuit that sought to block American Airlines and US Airways Group Inc. planned merger. The addition of Michigan to the list of plaintiffs was formalized through an amended complaint filed in court today. This was filed in a federal court in Washington. The lawyers of the Justice Department said in court last August 30 that it would be joining the suit against the planned merger.

The government lawyers wrote in the revised complaint, "The merger would eliminate head-to-head competition in hundreds of relevant markets and entrench US Airways' dominance at Reagan National Airport."

The amended filing also eliminated 29 routes from the list of city that US Airways and AMR Corp. would take once the merger goes through. The said routes would allegedly create high levels of concentration once the planned merger of the two airlines pushes through.

The US government and plaintiff sued the planned merger last August 13. They had argued that the merger would only reduce competition and hurt consumers. The US Airways-American Airlines merger would create the biggest airline company in the world.