Washington (CNN) -- The U.S. Air Force began grounding a third of its fighter jet fleet on Tuesday because of forced spending cuts, one of the most prominent consequences so far of government-wide austerity that began in March.
Dozens of units in the United States, Europe and the Pacific ultimately will stand down, according to a statement from Gen. Mike Hostage, the commander of the Air Force's Air Combat Command.
The move involving jets assigned to fighter, bomber, airborne warning and other squads aims to ensure that remaining units can maintain sufficient readiness through the remainder of the fiscal year, which ends September 30.
The cuts impact operations and maintenance, which must be implemented in part by flying approximately 45,000 fewer training hours through that period.
"We must implement a tiered readiness concept where only the units preparing to deploy in support of major operations like Afghanistan are fully mission capable. Units will stand down on a rotating basis so our limited resources can be focused on fulfilling critical missions," Hostage said.
"The current situation means we're accepting the risk that combat air power may not be ready to respond immediately to new contingencies as they occur," he said.
The Pentagon is expected to absorb about half of the $85 billion in sweeping budget cuts, called sequester, that resulted from the inability of Congress to reach a deal on deficit reduction.
The Defense Department had warned the cuts could threaten readiness. It is also expected to furlough civilian employees and cut contracts to meet the budget target.
Separately, the Navy on Tuesday announced it was canceling all the air shows its Blue Angels Flight Demonstration Squadron had scheduled for the rest of the year.
The Navy action follows the Air Force's April 1 announcement that its Thunderbirds team would not perform again this year.
Some units currently deployed, including A-10s, B-1s, F-16s and F-22s, will stand down after they return from their deployments. Others were grounded on Tuesday. The action will also impact certain Air Force Reserve and Air National Guard A-10 and F-16 squadrons.
"We're entering uncharted territory in terms of how we've had to take this year's cuts and make adjustments to mitigate the most serious impacts," Hostage said. "Remaining as mission-ready as possible for combatant commanders is our priority, and we're prioritizing spending to ensure this imperative is met."
Units that stop flying will shift their emphasis to ground training. They will use flight simulators to the extent possible within existing contracts, and conduct academic training to maintain basic skills and knowledge of their aircraft.