A new federal rule will make it easier for airline and railroad workers to join unions, handing organized labor one of its biggest victories under the Obama administration.
But the airline and railroad industries say that the National Mediation Board decision could lead to drawn-out labor disputes that would stifle commerce and cause passenger delays.
The new rule, which amends the Railway Labor Act of 1926, calls for the recognition of a union chapter 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, which meant that workers choosing not to vote at all were effectively counted as "no" votes.
The board proposed the rule change last year after a request from the AFL-CIO labor federation. That request came soon after President Obama named Linda Puchala — the former head of a flight attendant union — to a seat on the board, shifting the balance of power.
The rule, which passed by a vote of 2-1, will take effect 30 days after publication Tuesday in the Federal Register.
Supporters of the change say the old rule was undemocratic because an election's outcome was determined by a majority of those who voted. Unions long have accused employers of intimidating and even threatening workers from voting.
The Association of Flight Attendants-CWA, which represents more than 55,000 flight attendants at 20 airlines, said the NMB decision ushers in "a new era of democracy."
"Outdated and unreliable voting procedures have fostered a unique culture of voter suppression as companies understand that impeding union organizing merely requires preventing employees from voting," said a statement from the union. "Those days are now over."
But the Air Transport Association of America, a trade organization of leading U.S. airlines, said that the ruling, if left to stand, "undoubtedly will lead to more labor discord."
The group added that the NMB doesn't have the authority to implement the rule and will challenge the decision in court in the coming days.
"It is quite clear to us that the NMB was determined to proceed despite the proposed rule's substantive and procedural flaws," the transport group said in a prepared statement.
A spokeswoman with Delta Air Lines, where unions are trying to organize about 20,000 flight attendants, said the carrier "will join in support of a lawsuit when it is filed."
"While disappointed, we are not surprised by the majority members' decision in view of the way this rule change has been handled," said Delta spokeswoman Gina Laughlin.
The National Railway Labor Conference, which represents railroads in collective bargaining, said also said it was disappointed that the NMB rejected a decades old precedent that "has certainly not inhibited labor unions from gaining representation."
"We have seen nothing to suggest that the rule did anything other than help to foster stable labor relations in these important industries," said group spokeswoman Joanna Moorhead.
• This article is based in part on wire service reports.