JetBlue's roughly 5,000 flight attendants have voted to unionize, the New York-based airline said on Tuesday.

"While we respect the outcome of the election, we are disappointed in this result because we believe the direct relationship is superior to third-party representation," JetBlue said in a statement. The airline's pilots have already unionized and the flight attendants' vote means they will soon start negotiating with the carrier a contract that could include pay standards and job protection.

Most U.S. airlines' crews are unionized and JetBlue had been a non-union airline until its pilots voted to unionize in 2014. Delta Air Lines' flight attendants are not unionized, a rarity in the industry.

The flight attendants voted 2,661 to 1,387 to join the Transport Workers Union, the labor group said.

"The crewmembers want and deserve job security, representation and due process in disciplinary cases, improved wages and benefits, and a seat at the table in case of possible merger or acquisition," said TWU.

"As we move forward, we will work to come together around our mission to inspire humanity that has set JetBlue apart from other airlines since day one," JetBlue said.