A group of private airline pilots voted to decertify their Teamsters union local in an historic vote, announced Wednesday, that is the biggest of its kind in American history.

Flexjet is a private jet service that employs 600 pilots who voted in 2013 to join Teamsters Local 1108 following a merger with another carrier under the OneSky Flight banner. But months of voting required by the pilots being geographically dispersed culminated in a tally made public Tuesday.

Such decertification votes can be incredibly difficult compared to voting to join a labor organization. But the Flexjet vote is especially rare because it is the only time a pilots’ union has been decertified in the history of the Railway Labor Act, which was passed in 1924. Airlines were added a short time later, in 1936.

“We are very pleased with the outcome, although it was not a surprise as our pilot group has been dissatisfied and disappointed with Teamsters representation for years,” pilot Frank Woelke, who played a critical role in the decertification effort, told LifeZette. The pilots preferred working directly with management and believed the union’s benefits were insufficient to justify the cost of membership.

“We want to immediately extend two olive branches, one to our fellow pilots who supported the Teamsters and another to our company’s management team. Ultimately, we all want the same thing: a thriving company that offers all an opportunity for great careers,” Woelke said.

The National Mediation Board first required that a majority of pilots sign authorization cards for a “straw man” to represent them. Woelke, the straw man in the campaign, acted as a symbolic rival to the union during the election process. The pilots were then allowed to vote on whether to keep the union, write in an alternative union, or have no union.

The pilots preferred working directly with management and believed the union’s benefits were insufficient to justify the cost of membership.

The Teamsters Local 1108 could soon lose 600 pilots within its ranks, but that’s not yet certain. The union has questioned the legitimacy of the campaign and whether it’s being pushed by management.

Local 1108 has also claimed Flexjet failed to bargain in good faith after management informed them last year that it would not be implementing an agreement created during an arbitration process.

Connor D. Wolf covers Congress and national politics and can be reached at [email protected]. Follow him on Twitter