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Officials: Air patrols ending over New York, Washington

WASHINGTON (CNN) -- Mandatory around-the-clock combat air patrols over New York and Washington, conducted since September 11, are being discontinued, military officials said Tuesday.

The decision to end mandatory security flights over the two cities was implemented within the past few days, officials with North American Aerospace Defense Command (NORAD) said.

The system had involved the highest level of security for New York and Washington, where combat-ready warplanes had been flying patrols 24 hours a day, seven days a week.

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Between 10 and 20 other cities had been protected with random combat air patrols, and about 20 regions had a lower level of security involving "strip alerts" -- fighter aircraft on the ground at strategic airstrips, ready to fly within 15 minutes.

All three levels have been discontinued or scaled back.

The Pentagon said Tuesday it was adopting a "tiered approach," with combat air patrols and strip alerts at the discretion of NORAD, based on threat assessment and available resources.

"The combat air patrols are threat-based," said Brig. Gen. John Rosa, a Pentagon spokesman. "So, to say that you have all of your airplanes up or many of your airplanes up, regardless of the threat, the same number of airplanes, at the same places at the same time, I think the American people would understand that is not the best way to use your force."

Rosa would not confirm the end of flights over New York and Washington. "To tell you which airplanes are airborne when ... I'd be remiss to do that," he said.

Patrols will be flown during special events such as the Olympics, or wherever the president is traveling, NORAD said.

When a cutback in air patrols over New York initially was suggested in March, politicians and others protested, saying the move would send the wrong signal to potential terrorists.

U.S. officials maintained that a scaled-back patrol schedule would have to be considered, citing the high cost of equipment and personnel. Officials also pointed to improvements in airport security to minimize the chance of airline hijackings.

According to military sources, it has cost $500 million since September 11 for security air patrols nationwide, involving 250 airplanes and 13,000 military personnel. The deployment has intercepted questionable aircraft, or otherwise responded, more than 300 times.