ATLANTA — The union representing pilots at UAL Corp.'s United Airlines urged Chief Executive Glenn Tilton to resign Monday, accusing him of steering the nation's No. 2 carrier down a path to poor customer service, employee morale and financial performance.

A spokeswoman for the Chicago-based airline did not immediately respond to an e-mail seeking comment.

The pilots have stepped up criticism of United's top executives in recent months, angry that they have not gotten additional compensation since their pay was reduced sharply during the company's bankruptcy restructuring from 2002-06. Their pension was also terminated while UAL was under Chapter 11 bankruptcy protection.

In a statement, the United chapter of the Air Line Pilots Association said United needs new leadership. It launched a Web site to draw attention to what it says have been Tilton's failures since he took over as CEO in September 2002.

"Under Glenn Tilton's tenure, United has gone from being the finest airline in the world, with the best route structure and safety record, to a shell of its former self," said Capt. Steve Wallach, chairman of the pilots union's executive committee. "He has had every opportunity to turn this company around, and tap the abilities of its first-class employees, but instead he has run it into the ground."

The Transportation Department said last week that United had the second-worst on-time rate in June, with 59.3 percent of flights arriving at scheduled times. Overall, the nation's airlines were on time more often in June compared to a year ago.

The United pilots union also cited a recent survey conducted by United that revealed that only 38 percent of United employees take pride in United, down 15 percentage points from 2006.

"This is not a personal attack on Glenn Tilton," Wallach said. "These dismal numbers speak for themselves. They are a reflection of his inability to lead, his incompetence as a manager and his failure in virtually every category that can be measured. We have tried every conceivable way to convince him to invest in, and maximize the goodwill of, his employees. He has failed miserably."

In March, United said it planned to ground as many as 20 airplanes, or 4 percent of its fleet, and further cut capacity in 2008 to soften the blow of soaring oil prices. At the time, United's pilots criticized the plan, saying that "shrinking the airline to achieve profitability has been demonstrated to be a failed business practice."

Before joining United, Tilton, 60, was vice chairman of the board of directors of ChevronTexaco, as well as interim chairman of Dynegy Inc. Previously, he served as chairman of the board and chief executive of Texaco Inc., a position he assumed in February 2001.