The Pentagon is bracing for spending cuts far deeper than what it was expecting just a few weeks ago, including the possible elimination of an aircraft carrier group and other weapons programs, as an increasing number of lawmakers float proposals for slashing the once-sacrosanct defense budget.

Defense officials have been warning for months that the Pentagon must prepare for a new era of austerity after a long period of growth that has swelled military spending to its highest level, adjusted for inflation, since World War II.