While no detailed planning was under way for how to implement the automatic budget cuts, Hale said the Pentagon would act to protect war-related spending and safeguard multiyear contracts signed with industry to avoid penalties.

“You will not see cataclysmic changes,” Hale said.

He also appealed to weapons makers to continue efforts to reduce overhead costs, noting that labor costs had risen more sharply in the defense business than the commercial sector.

Chief executives from Northrop, Lockheed, Boeing and others told investors they were working hard to consolidate facilities, reduce their workforces and cut other overhead costs as they prepared for leaner times.

The Air Force is already facing difficult challenges in modernizing its aging fighter jets, bombers, helicopters, satellites and other equipment -- but those problems will get worse if Congress cuts the Pentagon budget further, Air Force Secretary Michael Donley told the conference.

He said the Air Force was already making tough choices about which programs to fund, while leaving some needed programs - such as new training aircraft, more modern nuclear equipment and updated surveillance radar planes -- unfunded for the moment.

“We’ll need to be careful -- and in some cases skeptical -- about adding more programs than we can afford,” Donley said.

He declined comment when asked whether further budget cuts would force the Air Force to abandon its plan to buy new combat search and rescue helicopters, saying only that current aircraft were 22 years old on average.

Boeing’s defense chief Dennis Muilenburg told the conference that his company had based its strategic plans on a worst case scenario that assumed that sequestration would occur.

“We try to be very realistic about those risks,” he said, adding that Boeing believed it was well-positioned for long-term growth despite mounting pressure on the U.S. defense budget.