CHICAGO (Reuters) - Flight attendants at Alaska Airlines have rejected a three-year tentative labor agreement, their union said on Wednesday.

The Association of Flight Attendants-CWA, which represents flight attendants at the Seattle-based carrier, said it will survey its members to determine key issues and return to the table to address them.

The tentative deal offered an average pay increase of 32%. It was also the first agreement to make boarding pay legally binding for unionized flight attendants.

Flight attendants in the U.S. are usually paid an hourly rate after the flight cabin doors close and it does not include the time taken to onboard passengers.

"This is democracy in action and Flight Attendants always have the final say on any contract," the union said in a statement. "There is more work to do."

Alaska Airlines did not immediately respond to a request for comment.