Executives at Northwest Airlines and Delta Air Lines had hoped to get at least the Northwest pilots on board before announcing their merger.

Instead, they wound up 0-3 with Northwest's three large unions.

The pilots, ground workers and flight attendants are all opposing the merger, and for the latter two groups, their survival as union members may be at stake. At Delta, the ground workers and flight attendants are nonunion, and they outnumber their counterparts at Northwest.

The deal to create the world's largest airline was announced late Monday. The unions can't block the merger if it is approved later this year by the U.S. Justice Department, but they said Tuesday the deal cannot achieve its promise without their cooperation.

"Airline employees are right to ask if this is a recipe for failure on a grand scale," Stephen Gordon, president of District 143 of the International Association of Machinists (IAM), wrote to the union's members. IAM members, Gordon said, will be "taking action in the halls of Congress, visiting politicians in their home states and participating in rallies nationwide."

Leaders of Northwest's Air Line Pilots Association (ALPA) also reiterated their opposition to the merger on the basis of Delta's new contract with its pilots and failure to integrate the two pilot groups in terms of seniority, which affects pay and flight schedules.

"The labor discord which will result from the current structure of the merger is likely to overwhelm the potential economic positives," said Dave Stevens, chairman of ALPA's Northwest group. "They cannot be successful without the support of all employees."

Until they get a new contract, Stevens said Northwest pilots would follow the letter of their contract -- the so-called scope provisions -- which can affect the airline's ability to incorporate flexibility in its flight scheduling. That could make it more likely that Northwest could run into troubles with delays or cancellations during the summer travel season if the airline doesn't have a sufficient number of pilots ready to fly.

The Association of Flight Attendants (AFA), which represents Northwest's flight attendants, is in the middle of an organizing drive with Delta flight attendants which could smooth the transition if the union drive prevails.

But if the Delta attendants don't vote to join the AFA, Northwest's flight attendants could lose their union coverage, since a majority of a work group must vote to have a union in place.

"It wouldn't be a good scenario," Kevin Griffin, AFA Northwest president, said. "We'd be at the company's will, and at Delta that changes often."

Delta's promises that the merger would protect frontline employees who deal directly with passengers also met with a skeptical response from some Northwest union leaders.

"There's no guarantee in this economic climate. Anything can change," Griffin said.

John Budd, a labor economist at the University of Minnesota's Carlson School of Management, said airlines must consolidate in a climate that includes $110-a-barrel oil. He can't envision a merger that doesn't include layoffs.

"There has to be economic gain to make the merger work," Budd said. "It's hard to see where that comes from without some job loss."

Even if the companies hold true to their promises, it could take years for Northwest workers to fully accept their new bosses.

"In the long run, the larger company's culture wins out, but not overnight and not easily," Budd said. "There are still people at Northwest who are upset from the Republic merger, and that was 20 years ago [1986]. The question is how long will it take to really integrate the groups and integrate operations."

David Phelps • 612-673-7269