As International Association of Machinists President Tom Buffenbarger prepares to retire, he sees promising signs for the union's aerospace and airline workers.

The IAM requires that in the month when executives reach 65, they retire. Buffenbarger, who was first elected IAM president in 1997, turned 65 on Dec. 14, and will swear in successor Bob Martinez on Jan. 4.

In a tough time for labor unions, the IAM has persevered as the biggest aerospace and airline union. It represents about 35,000 workers at Boeing (BA) - Get Report and about 30,000 more at United (UAL) - Get Report . Both companies have recently seen the appointment of new CEOS that seem generally more favor to labor.

Boeing, Buffenbarger said, has long been a company that "would prefer not to have any union," but he sees hope for change following the July 2015 appointment of Dennis Muilenburg to replace the retiring Jim McNerney as CEO.

As Boeing increases production rates, "it takes cooperation between management and workers," he said. "To make it all work and to deliver all those airplanes that are backlogged, on time, and to maintain the quality Boeing is famous for, he needs the relationships with employees."

From 2003 to 2015, Boeing was run by two executives, Harry Stonecipher and McNerney, who had worked under Jack Welch at General Electric, "one of the most notorious companies in the country for its view on labor unions," Buffenbarger said.

During a July conference call, Muilenburg declared: "I had a chance to start with Boeing 30 years ago in Puget Sound, so I have a very deep appreciation of our workforce there. This idea of mutual appreciation and partnerships, and investment in our people is very important to me, and will continue to be important."

Buffenbarger also sees promise at United, where IAM represents roughly 30,000 fleet service, passenger service and stockroom employees. CEO Jeff Smisek was forced down in September and replaced by Oscar Munoz.

The two parties said last month they would open negotiations on a new contract more than a year early, and the carrier said it would not outsource union jobs for the next three years.

Buffenbarger said he was pleased by Munoz's appointment. As CEO of CSX, Munoz had a good relationship with IAM railroad workers. Then "he hit the ground running at United: He said publicly he wanted to improve the relationship between employees and the airline. If you have a satisfied workforce, it will do what it takes to make the airline attractive."

 Munoz, who suffered a heart attack in October, is scheduled to return to United in the first quarter.

 Meanwhile at American, the IAM and the Transport Workers Union are negotiating jointly for a new contract with approximately 30,000 workers. Before a memrger, IAM represented mechanics and fleet service workers at US Airways.

"The two sides have agreed on goals for negotiations," Buffenbarger said. "The company wants to get to an agreement where they can finalize single carrier status and buckle down to start running an airline and make it work.

Buffenbarger said his airline industry failure was the loss of about 12,500 jobs in the 2008 merger between Northwest and Delta. IAM represented about 12,000 Northwest agents and ground workers, but the union was unable to win any representation elections at Delta. "For the sake of consolidation and corporate profits, we lost jobs that belonged to good people," he said.

This article is commentary by an independent contributor. At the time of publication, the author held no positions in the stocks mentioned.