The Communications Workers of America's effort to organize American Airlines' passenger service agents has failed by 150 votes.
The union tweeted on Tuesday afternoon that 2,902 agents voted in favor of a union while 3,052 voted against unionizing. There are about 9,700 passenger service agents at American.
Although not all of the passenger service agents cast votes in the representation election, the CWA only needed a majority of the votes cast to win the right to represent the workers.
American spokeswoman Missy Cousino said the carrier was pleased its employees chose to remain independent.
"American thanks everyone who took part in this election," Cousino said. "The company looks forward to continuing to work closely and directly with our Agents and Representatives as we build the new American Airlines."
The CWA had originally filed its application for a representation vote with federal authorities in December 2011, however the vote was not held until a year later because American had filed several legal challenges to stop the vote.
The Fort Worth-based carrier had claimed the union did not collect authorization cards from 50 percent of workers, as required by a new law enacted in February. The National Mediation Board, which oversees union representation votes, had argued that the previous 35 percent standard should be used since the application for an election was filed under the old standards.-Andrea Ahles