Opponents of the proposed merger of American Airlines and US Airways are suing to block the deal, saying it would hurt consumers by driving up airfares.
The lawsuit was filed in San Francisco federal court by antitrust lawyer Joseph Alioto on behalf of nearly 40 consumers.
Alioto argues that the merger would lead to fewer flights, reduced service to small cities, and a lower quality of service overall. It would leave four airlines - United, Delta, Southwest and the post-merger American - controlling about 90 percent of the domestic airline industry, leading to higher prices.
And American Airlines spokesman called the lawsuit "baseless," and a US Airways spokesman says it lacks merit.
The U.S. Justice Department is reviewing the proposed merger, which would make American the world's biggest airline.
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