Delta Air Lines and its pilots union on Friday said they have reached a deal on a new labor contract.

The agreement in principle comes after months of mediation and informational picketing by pilots pushing for higher pay. Atlanta-based Delta has about 13,000 pilots.

In recent talks, the company had proposed a 27 percent pay boost over four years, while the union sought a 31 percent raise over three years. Pilots have said they want to recover from pay cuts during the company’s past financial challenges and bankruptcy, now that Delta is making billions of dollars in profits.

The next step is for union leaders to review the full language of the agreement reached by negotiators. If leaders approve the deal, it will be sent to rank-and-file pilots for a vote.

Details weren’t released. John Malone, chairman of the pilots union at Delta, issued a statement saying the new agreement “achieves the goal of advancing the profession while raising the bar for all airline industry pilots.” Delta pilot pay rates are closely watched by rival carriers and other pilot unions, and can influence others in the industry.

Delta called the deal an “industry-leading package of pay, benefits and work rules.”

This is the second round of talks to reach a deal. A previous contract agreement reached last year — which included raises of more than 21 percent over three years — was rejected in voting by rank-and-file pilots.

Issues with pay, profit sharing and sick leave were among the concerns raised by pilots who voted against that proposed contract. The defeat led to a change in union leadership and Malone’s election as union chairman.