Delta Air Lines, the most profitable U.S. carrier, is raising pay for nonunion employees as it gets ready for another attempt by a union to represent its flights attendants.

CEO Ed Bastian told Delta employees Monday that the airline will boost pay for flight attendants and ground workers by 5%, raise the minimum wage for U.S. workers to $19 per hour, and set aside money for merit raises.

Delta said the increases affect more than 80,000 employees.

"With this increase in base pay and starting rates, we continue our commitment to provide Delta people with industry-leading total compensation for industry-leading performance," Bastian wrote in a memo to staff. He said the company has raised pay among major work groups by a cumulative 20% to 25% since 2022.

That figure includes base pay and profit-sharing. Delta gave employees $1.4 billion in profit-sharing for 2023.

Delta earned $4.6 billion last year — more than United, American, Southwest and Alaska airlines combined. It was Delta's biggest profit since 2019, before the pandemic affected U.S. travel.

About 20% of the Atlanta-based airline's workers are represented by unions — by far the lowest percentage among the nation's four biggest airlines. Delta pilots are represented by the Air Line Pilots Association, but cabin crews, maintenance workers and others are nonunion. Flight attendants narrowly voted against unionizing in 2010, and previous organizing campaigns failed in 2002 and 2008.

The Association of Flight Attendants is trying to change that. President Sara Nelson said her union hopes to gather enough authorization cards from Delta attendants by the end of the year to trigger another election.

"Delta has become the leader in generating profits, and that means Delta flight attendants should be leading on pay and benefits, and they are not," she said.

Nelson believes that unions are in a stronger place now, even in the largely nonunion South, where the United Auto Workers won an election last week at a Volkswagen plant in Tennessee. Nelson's union is seeking an industry-leading contract at United Airlines, which could bolster its case at Delta.