The Pentagon is looking at ways to scale back the round-the-clock combat air patrols fighters have been flying over the United States since the September 11 terrorist attacks.
Since the terrorist attacks on New York and Washington, the military has conducted some 13,000 air patrol missions at a cost of more than $324 million.
The operation involves an estimated 11,000 personnel and more than 250 aircraft - fighters, tankers and airborne surveillance planes.
Now defense officials say they are considering options for cutting back the operation.
For security reasons, Chief Pentagon spokeswoman Victoria Clarke will not confirm or deny any plans to reduce the air patrols.
But Ms. Clarke tells reporters the Pentagon intends to maintain the appropriate level of security for the American people. "It's important to emphasize that we are absolutely committed to providing the best protection possible for the American people," she said. "And combat air patrols are part of those. And we'll dedicate the right resources and the right numbers of resources to get the job done."
The missions are mainly being carried out by the Air Force Reserve and the Air National Guard. They are reportedly putting a severe strain on both the personnel and equipment involved.
Air Force officials say that since September 11, military aircraft have responded more than 200 times to alerts for such problems as unidentified planes, violations of restricted airspace and reported in-flight emergencies.
On 92 of those cases, jets on alert on the ground were scrambled. Jets already in the air were diverted on the other 115 occasions.
The military has been authorized to shoot down commercial aircraft if necessary to avoid any recurrence of the September 11 attacks. Those were carried out by suicide terrorists who commandeered jetliners and crashed them into the World Trade Center and the Pentagon, killing more than 3,000 people.