CHARLOTTE, N.C. -- The relationship between the management and pilots at American Airlines is going through a bit of a bumpy patch, to put it mildly.

In a harshly worded letter sent last month to CEO Gerard Arpey, leaders of the Allied Pilots Association concluded this way: "Enjoy your blood money and your union-busting meetings. We'll see you in court, in the newspapers, and on the picket line."

Pilots contended in the letter that American's effort to maximize revenue by reducing capacity deprives pilots of career opportunities, "while more and more VPs are hired."

They suggested that an unnamed pilot, forced off his medications in the drive to cut costs, may try to kill himself, and they decried a management bonus of stock worth about $250 million.

The pilots also attacked the airline's joint leadership team, a group of management and labor leaders who meet regularly, calling it "a cruel hoax perpetrated upon AA employees" and "a union-busting exercise." They said they would no longer participate in its gatherings.

American spokeswoman Sue Gordon said that at most carriers, unions are "crying out for more involvement" through methods such as the leadership team.

The letter, she said, reflects a move toward "a more traditional approach" to labor relations, "rather than a more collaborative or interest-based approach." While the airline prefers the latter, "We have experience in the more traditional approach," she said.

"We certainly recognize that heated rhetoric is common during contract negotiations," Gordon added. The text of the letter was first reported this week by the Fort Worth Star-Telegram.

Shares in AMR ( AMR), American's parent company, were trading Wednesday at $24.19, down 3.7%, the steepest decline among the airlines.

The pilot contract becomes amendable on May 1, and the two sides have been talking since September 2006. There has little apparent progress, as pilots have sought to regain ground after accepting reduced pay and benefits in order to help the airline avoid bankruptcy in 2003.

Last spring, American rejected a union proposal for a 30.5% pay increase and a signing bonus. In a subsequent union election, the winners were pilots who pledged to take a harder line than the incumbents they ousted.