Two Air Force squadrons of C-17 transport aircraft are being inactivated over the next two years as a cost-saving measure, the service announced.

The two squadrons -- 16 planes in all -- are located at Joint Base Charleston, S.C., and Joint Base Lewis-McChord, Wash.

The inactivation, the Air Force said, is based on President Barack Obama's defense budget for fiscal 2015.

"In this fiscally constrained environment, we have to balance readiness, capability and capacity," said Maj. Gen. Michael S. Stough, the AMC Strategic Plans, Requirements and Programs director.

"To best preserve this capability, the intent is to fund these aircraft back into primary mission aircraft inventory in future years, and transfer them to the Reserve Component -- and we're working with our Air National Guard partners to do that, perhaps even as early as FY16.

"We rely on our total force partners to meet our global mobility requirements; we couldn't do the mission without them. We'll continue to leverage the unique strengths of the active and Reserve components to meet current and future requirements with available resources," he said.

The fiscal year 2015 budget transfers the 16 aircraft from the primary mission aircraft inventory to backup aircraft inventory. As part of the backup inventory, the planes will continue to receive funding to support weapon system sustainment but there will be no funding to assign personnel to the aircraft or to aircraft flying hours.

The Air Force said the move will save about $110 million annually.