DALLAS >> Pilots at Southwest Airlines have overwhelmingly approved a new contract that will raise their pay rates by nearly 50% by 2028, becoming the last group of pilots at the nation’s four biggest airlines to score huge raises.

The Southwest Airlines Pilots Association said Monday that the agreement covering pay and other issues for about 11,000 pilots was ratified by a 93% to 7% margin.

Airline labor groups — and pilots in particular — have succeeded in negotiating pay raises over the past year as most U.S. have returned to solid profitability coming out of the pandemic. Pilots have been helped by a shortage, particularly at smaller carriers that act as training grounds for American, Delta, United and Southwest.

The Southwest agreement followed more than three years of bargaining.

“This has been a long time coming and it is only through the unity of our pilot group that we were able to achieve the gains in this contract,” said pilots’ union President Casey Murray. He said the agreement gives pilots “the security and protections that have been long needed.”

The airline’s vice president of labor relations, Adam Carlisle, said the contract “justly rewards our pilots and supports our operational needs.”

Southwest said the five-year deal gives its pilots “industry-leading compensation” and has a new process for assigning pilots to flights during unusual events. The union said Southwest’s process contributed to nearly 17,000 canceled flights during and after a winter storm in December 2022.

The contract calls for an immediate 29.15% increase in pay rates upon ratification, followed by 4% raises in 2025, 2026, and 2027 and a 3.25% increase in 2028. Cumulatively, that works out to just under 50% over the life of the contract.

The union said the contract also includes changes to pilot retirement, scheduling and parental-leave programs.