Which significant organizational change occurred in 1935?

The significant organizational change that occurred in 1935 was the transfer of all tactical units to a single GHQ (General Headquarters) commander. This action was part of a broader effort to streamline command structures and improve operational effectiveness within the U.S. Army Air Corps. Centralizing control under a single commander allowed for better coordination and execution of air operations, aligning air power more closely with ground forces and facilitating joint operations.

This restructuring was crucial in preparing the Air Corps for more integrated and coordinated activities during World War II. It shifted the focus away from a more scattered command structure, promoting efficiency and effectiveness in air warfare strategy.

The other options, while significant in different contexts within military aviation history, did not occur in 1935. The formation of the Army Air Forces happened later, in 1941, as did the establishment of the Air War Plans Division. The creation of Air Corps training centers also took place outside of that specific year and was part of ongoing efforts to enhance training and preparedness in aviation. Thus, the correct choice highlights a pivotal moment in the evolution of U.S. military command structures.