American Airlines faces a fresh controversy over executive pay after one of its largest unions on Thursday revived a campaign against Chairman and Chief Executive Gerard Arpey.

The Transport Workers Union of America is backing a series of ads that feature an online game inviting users to guess Arpey's annual compensation.

The move opens up a fresh front amid long-running employee grievances over executive compensation at American, which steered clear of bankruptcy protection in 2003 with the help of employee concessions.

Union action has become an annual ritual since a new performance pay scheme kicked in at American in 2006.

The harmonious labor relations that fostered cost-cutting deals under American's "Working Together" initiative have long since soured, with sporadic protests by flight and ground personnel over the past three years.

"What makes it so frustrating at American is that we worked with management, making concessions beginning in 2003, and finding new ways to generate revenue," said TWU President James Little in an interview.

American and the TWU last month asked federal mediators to help revive contract talks after the two sides failed to agree on negotiating terms.

Little said that the recent nomination of Linda Puchala to head the National Mediation Board should shorten the timescale for contract talks.

The national advertising campaign focused on Arpey represents a change of tack: unions had previously focused on a swathe of executives qualifying for cash and share payouts.

Efforts involving the TWU and unions representing pilots and flight attendants successfully forced the airline to remove the cash element of executive compensation.

American, a unit of AMR Corp. (AMR), has defended its performance-based compensation regime, which it said would make lower-than-expected payouts in mid-April because of the fall in its share price.

Rank-and-file staff believe they have not been properly rewarded for keeping the airline out of bankruptcy. Little estimated that employee concessions had saved AMR $6 billion, and said union members have not shared in those gains.

American's latest spat comes amid a raft of contract talks across the U.S. industry, with many of the deals coming up for renegotiation.

Little said recently-completed talks with Southwest Airlines Co. (LUV) went smoothly "I think that Southwest believes that its employees are its number one asset, and that pays off for the airline."

United Airlines, a unit of UAL Corp. (UAUA) that has also seen harsh criticism from uniosn over executive compensation, said it is set to begin contract talks this month.

-By Ann Keeton; Dow Jones Newswires

312-750-4120;ann.keeton@dowjones.com