Government officials imposed stricter airport security measures after the failed Christmas Day bombing of a Northwest Airlines flight to Detroit. Such breakdowns are rare, officials said, but a government report released in October shows breaches at U.S. airports nearly doubled over five years. “That’s only the breaches we know about,” said Mike Boyd, president of the Colorado-based aviation consulting firm Boyd Group International. The Transportation Security Administration reported 1,442 security breaches at the nation’s 450 commercial airports in the fiscal year ended Sept. 30, 2004, according to the Government Accountability Office report.