Oct. 29 (Bloomberg) -- U.S. carriers including Delta Air Lines Inc. will have a harder time blocking union organizing campaigns under a change planned by a federal labor board, people familiar with the matter said.

The proposal, to be announced in coming days, would let workers form unions with majority approval of those voting, according to the people, who asked not to be identified discussing the plan. It would overturn a standard that requires support of most workers in a class, not just those who cast ballots.

The change would be a victory for the AFL-CIO, the largest U.S. labor federation. The group asked the National Mediation Board to overhaul the voting standard last month, saying it would be more democratic.

“It’s been our sincere hope that the National Mediation Board would look at our recommendations favorably,” Edward Wytkind, head of the AFL-CIO’s transportation trades department, said in an interview yesterday.

A National Mediation Board spokesman didn’t return a telephone call seeking comment.

Delta, the least unionized major passenger airline, has fought the proposed change. Pilots are the only large work group completely organized at the Atlanta-based carrier.

“We do not believe the NMB has the authority to change these long-standing rules,” Delta spokeswoman Gina Laughlin said in an interview. “Nor do we believe a minority union should be allowed without giving employees a similar process to vote out a union.”

Attendants and Machinists

The Association of Flight Attendants-CWA made a request to the board in July that would pave the way for an election at Delta, and the International Association of Machinists and Aerospace Workers asked a month later. Both unions are AFL-CIO members.

The flight attendants want to organize 20,500 employees, including non-union workers at Delta and those organized at Northwest Airlines, which Delta purchased last year.

The machinists are seeking a vote for about 14,000 baggage and ramp workers, flight-simulator technicians and security guards. The former Northwest employees in this group had been in unions while Delta’s workers weren’t.

The U.S. Chamber of Commerce and the Air Transport Association, a trade group for major U.S. carriers, also oppose the change.

“If the NMB goes forward with its proposal, we will be enormously disappointed, as nothing has changed to warrant a new rule,” James May, the Air Transport Association president, said in a statement.

Three-Member Board

The National Mediation Board helps resolve labor disputes and oversees elections for airlines and railroads under the Railway Labor Act. The three-member board, criticized by labor for actions under Republican President George W. Bush’s administration, now has a Democratic majority with President Barack Obama in office.

The Obama administration added a former flight-attendants’ union leader to the board in May, replacing a former lobbyist for Northwest Airlines. Another board member is a former pilot- union official.

To contact the reporters on this story: John Hughes in Washington at jhughes5@bloomberg.net.

Last Updated: October 29, 2009 00:01 EDT