Authorities have captured a senior al-Qaida operative in Southeast Asia who had been assigned to recruit new pilots to conduct Sept. 11-style suicide hijackings in the United States, the White House said Thursday. Hambali, an Indonesian whose real name is Riduan Isamuddin, was detained this week during a joint operation run by the Central Intelligence Agency and a foreign government in Southeast Asia. American officials declined to identify that government, although foreign newspapers reported Hambali was taken in Thailand.