Updated

The Dallas and Fort Worth chambers of commerce and union pilots at Texas-based American Airlines say the state's attorney general should support American's proposed merger with US Airways instead of fighting it in court.

The presidents of both chambers said the merger will help the local economy and create jobs, and the alternative is economic uncertainty for the region and state. The combined company would be based in Fort Worth.

"By any stretch of the imagination, having what the press refers to as 'the World's Largest Airline' based in Texas, makes our state more competitive," James Oberwetter of Dallas and Bill Thornton of Fort Worth wrote Monday in an open letter to Abbott.

The pressure on Abbott from the business community comes just weeks after the Republican announced his candidacy for governor in the 2014 election.

Separately, the Allied Pilots Association said in an advertisement in Monday's Dallas Morning News that American is "a powerful economic engine" in Texas but needs the merger to compete with bigger United and Delta.

The union asked Abbott, "Are you opposed to having a leading global carrier in Fort Worth? Considering everything at stake — including the large number of jobs and the tax revenues they generate — that doesn't make any sense."

Abbott's office didn't respond immediately. Last week, Abbott wrote in a column for the same newspaper arguing that the merger was designed to eliminate competition and raise prices.

Abbott and AGs in five other states joined a U.S. Justice Department lawsuit that seeks to block the merger on antitrust grounds. The airlines vowed to fight back in court, and they left open the possibility of negotiating a settlement that would allow the deal to go ahead.