U.S. wary of al-Qaida attack on aviation

WASHINGTON, April 29 (UPI) -- A top U.S. counter-terrorism official said Sunday al-Qaida apparently still is open to a plot to attack commercial aviation as it did on Sept. 11, 2001.

John Brennan, chief counter-terrorism adviser to President Obama, said Sunday while al-Qaida has been significantly weakened, a high state of vigilance is still needed in the air-travel industry.

"Aviation has been a traditional target of al-Qaida and they continue to do that," Brennan said on ABC's "This Week."

Brennan agreed the slaying of Osama bin Laden a year ago was a major development in what he said was the overall degradation of al-Qaida capabilities.

Brennan said the reputed new leader, Ayman al-Zawahiri, does not have the same charisma and "institutional support" within al-Qaida that Bin Laden enjoyed. But at the same time, al-Qaida's operations in Yemen remain a particular concern.

"They have demonstrated both the intent, as well as the capability to try to carry out an attack," he said.