A vote to recall the head of United Airlines’ pilots union has been postponed until Thursday, sources told the Tribune.

Captain Wendy Morse, the first woman to head a major U.S. pilots union, faced a possible ouster as United’s Air Line Pilots Association leaders gathered for a quarterly meeting in Chicago on Monday. Morse, through a spokesman, declined to comment.

After hours of debate in a room packed with Morse loyalists, the union’s leaders opted to push the vote back to later in the week. Since the recall is an agenda item, under the union’s parliamentary procedures, the action taken may not be a simple up or down vote by the master executive council. The council’s options include to discuss the item, defer it, reject it or to vote to take no action.

A defeat of Morse could signal the start of labor strife that new United CEO Jeff Smisek has sought to avoid as he melds recently merged Continental Airlines and United into the world’s largest carrier and negotiates contracts with every employee group, analysts said.

The mayhem is unusual even for the cutthroat world of airline pilot politics, sources said. Morse, who had been elected chairwoman by a single vote, survived a recall effort before she took office at the start of 2010. The leaders of the union’s Washington, D.C., pilots’ council also face a recall vote on April 22 for aiding the latest effort to dump Morse.

The turmoil reflects a longstanding philosophical divide among airline pilots over whether or confrontation or open dialog is the better way to deal with management under the federal laws that tightly restrict job actions by aviation labor. Over the past two years, both American Airlines and United pilots had voted out militant pilot leaders.

United’s master executive council, whose members set policy and elect the union chairman and other officers, remains almost evenly split between those who favor a get-tough approach to management and moderates such as Morse, who favor keeping channels of communication open and hammering out differences in private.

Since United merged with Continental last year, frustration has grown among rank-and-file pilots over the deliberate pace of talks for a joint contract with management of United Continental Holdings Inc., the carriers’ Chicago-based parent company. United pilots are eager to get out of a bankruptcy-era contract that slashed average pay by about 40 percent.

The resolution to oust Morse came out of a no-confidence vote approved by the Washington council March 25, according to documents obtained by the Tribune. The measure claimed Morse was an ineffective leader who wasn’t using the union’s leverage to speed up talks.

Council chairman Steve Brashear didn’t return phone calls.

“Whereas we continue to be saddled with the ‘wait and see’ responses from her with respect to our contract,” the resolution stated. “While we ‘wait and see,’ United management is saving millions of dollars on the backs of this labor group once again.”

Morse’s supporters claim she is being used as a scapegoat, and that contract talks, while cumbersome, are moving forward. They say ousting Morse could inflame divisions among Continental pilots and lead to a situation like US Airways’, whose deeply-divided pilots are stuck with a bankruptcy-era contract six years after merging with America West Airlines.

If the recall occurs, “what follows in terms of the culture between the pilots and United Airlines is going to make what is going on at US Airways look like a day at Disney World,” predicted a United pilot who asked not to be identified because he wasn’t authorized to speak publicly. “And anybody who thinks that a contract would result from the mayhem created by that culture is living in a fantasy land.”