The International Association of Machinists and Aerospace Workers District 75 and Local 2003 cited Lockheed's "hostile" management style.
"Lockheed Martin is known for confrontational management practices at numerous locations where it provides services to the U.S. government, causing serious harm to the labor-management relationship," said District 75 President Steve Pridgen.
"A hostile management style may win applause from Lockheed's Wall Street allies, but it can be a death sentence to surrounding communities like ours.
"We're very concerned that as a temporary contractor, Lockheed could undermine the mission at Fort Rucker as well as the community at large."
The Army is considering Lockheed Martin and three other contractors for selection as prime contractor at the post, administering a wide range of services. The Army is expected to announce its decision soon.
The union says nearly 3,500 civilian workers at Fort Rucker are represented by it.
"The IAM-represented workforce at Fort Rucker is understandably proud and protective of their contributions to our nation's armed forces and communities," said IAM representative Tony Blevins.
"As the U.S. Army's primary location for Army Aviation Excellence in rotary-wing flight training from initial to advance flight programs, we have accumulated approximately eleven million accident free flight hours without a maintenance-related accident. We intend to protect that record from a short-sighted management style with a singular focus on profits."