DALLAS — American Airlines and US Airways expected to spend this week cruising toward completion of their huge merger, a deal that was worth $14 billion on paper and would create the world's biggest airline.
Instead, they were stunned Tuesday when the federal government and six states sued to block the deal, saying it would hurt competition and cost consumers hundreds of millions of dollars a year in higher fares and extra fees.
Antitrust regulators had done little to interfere with three other big airline mergers in the past five years, so they were not expected to stand in the way of American and US Airways. But this latest deal would leave four airlines controlling more than 80 percent of the U.S. air-travel market.
The Justice Department turned the words of US Airways leaders against them. The 56-page lawsuit filed in federal district court in Washington, D.C., was peppered with quotes from internal emails, investor presentations and public comments in which the airlines' top executives noted that previous mergers had helped lead to higher fares and higher fees to check a bag or change a ticket.
Executives of the two companies vowed to challenge the lawsuit.
"We will fight them," declared US Airways CEO Doug Parker, who would run the combined company.
Paul Denis, a Washington antitrust lawyer hired by US Airways, said Tuesday was the Justice Department's "best day."
"They got to hold their press conference. Now they've got to try their case in court," he said.