WASHINGTON (AP) -- In a major victory for organized labor, unions will have an easier time signing up airline and railroad workers after the Obama administration Monday changed a 76-year-old rule on union elections.
The change is the most significant so far in a string of White House moves designed to boost unions, which are struggling to reverse years of decline in membership.
The new rule, announced by the three-member National Mediation Board, would recognize a union if a simple majority of workers who cast ballots approve organizing. The previous rule required a majority of the entire work force to favor unionizing. That meant workers choosing not to vote at all were effectively counted as "no" votes.
Airlines that fought the change say it will lead to more labor disputes that could disrupt commerce and increase delays in an industry already reeling from recession, higher fuel costs and stepped-up security measures.
The most immediate impact of the change would be at Delta Air Lines Inc., where unions are trying to organize about 20,000 flight attendants. Unions are also expected to target workers at smaller carriers, including Allegiant Air, JetBlue Airways, Republic Airways and SkyWest.
"We applaud the NMB for taking this historic and courageous step to bring democracy to union elections," said Patricia Friend, president of the Association of Flight Attendants-CWA.
But the Air Transport Association, which represents most major airlines, is expected to file a lawsuit challenging the new rule.
"It is quite clear to us that the NMB was determined to proceed despite the proposed rule's substantive and procedural flaws, leaving us no choice but to seek judicial review," the industry group said in a statement.
The rule will take effect 30 days after publication Tuesday in the Federal Register. The flight attendants' union said it would seek a representation election at Delta soon afterward.
Proponents of the change say the old rule ran contrary to democratic standards, where the outcome of an election is determined by the majority of those who vote. The change puts union elections at airlines and railroads under the same procedures followed by most other companies, which are overseen by the National Labor Relations Board.
"After decades of operating within a system that is rigged against them, rail and aviation workers have at least gained a right that most of us take for granted," said Edward Wytkind, president of the AFL-CIO Transportation Trades Department.
The board proposed the rule change in October after a request from the AFL-CIO. That request came soon after President Barack Obama named Linda Puchala -- the former head of a flight attendant union -- to a seat on the board, shifting the balance of power.
The final rule was approved 2-1, with chairwoman Elizabeth Dougherty issuing a fierce dissent. Dougherty, appointed by President George W. Bush, said the change is "an unprecedented departure for the NMB and represents the most dramatic policy shift in the history of the agency."
Delta spokeswoman Gina Laughlin said Delta would support an industry lawsuit challenging the rule change.
"While disappointed, we are not surprised by the majority members' decision in view of the way this rule change has been handled," Laughlin said.
Airlines and railroads employ more than 500,000 workers, and about two-thirds of those are already in unions. That's much higher than the overall union membership rate of 12 percent.
One exception to the higher rate of union representation is at Delta, where only about 15 percent of workers were union members before the carrier merged with heavily unionized Northwest Airlines two years ago. Unions representing flight attendants and ground workers who worked for Northwest want the new rules to cover elections at the combined carrier.
In a 2008 election, 5,253 Delta flight attendants voted to be represented by the AFA. But the union lost under the old election rules because the roughly 8,000 flight attendants who didn't vote were counted as "no" votes.
The new election rules will also help the International Association of Machinists and Aerospace Workers, which represents Northwest ground workers such as baggage handlers and gate agents. Delta says it has roughly 30,000 workers in that group, including roughly 10,000 who came from Northwest.
AP Airlines Writer Joshua Freed in Minneapolis contributed to this report.