United Continental Holdings Inc (UAL.N) said flight attendants from the former Continental Airlines ratified a new labor agreement.
The former United Airlines and Continental Airlines closed their $3.17 billion merger in 2010, forming the world's largest airline, now known as United Airlines.
One of the biggest obstacles to the completion of the merger had been the integration of two work forces with joint contracts.
The new agreement covers about 9,000 flight attendants who came from Continental, United Continental said in a statement.
The company said it would start negotiations with the Association of Flight Attendants on a new agreement that brings flight attendants at United, Continental and Continental Micronesia under a single contract.
Flight attendants from the company's United subsidiary ratified a new four-year contract in February.
(Reporting by Megha Mandavia in Bangalore; Editing by Anthony Kurian)