STEPHANOPOULOS: ...this morning. So you know, we know that Al Qaida pays attention to anniversaries. And security has been beefed up, especially at airports. Is there any indication that an actual plot is in the works?
BRENNAN: Well we are vigilant throughout the course of the year, but on a day that marks the one year anniversary of bin Laden being brought to justice, we are especially vigilant. At this time we don't see any active plot that is underway, but we are maintaining our guard. We are following every lead. There always are reports about Al Qaida trying to penetrate our defenses. But at this point, our counterterrorism professionals are doing their job, both here in the United States we well as abroad.
STEPHANOPOULOS: But the FBI and Homeland Security this week did say that they believe the Al Qaida affiliate in Yemen is making new efforts to target western airports.
BRENNAN: We're particularly concerned about Al Qaida in the Arabian Peninsula which is located in Yemen. They have demonstrated both the intent, as well as the capability to try to carry out an attack. With the underwear bomber, Christmas Day a couple years ago as well as trying to integrate an IED, Improvised Explosive Device into a printer cartridge that was going to come aboard a cargo plane here. They are continuing to try to again, carry out an attack against U.S. persons inside of Yemen, as well as against the homeland. We're working very closely with our Yemeni partners to track down all these leads. And on a regular basis...
STEPHANOPOULOS: Is it still focused on planes?
BRENNAN: Yes. Aviation has been a target -- has been a traditional target of Al Qaida. They continue to do that. 09/11 obviously they used aircraft as weapons. So we need to maintain our vigilance, clearly overseas at these last points of departure and making sure that we're doing everything that we can to work with our -- our partners internationally to -- to protect the traveling public.
STEPHANOPOULOS: Do they have the capability now to carry out anything like a 09/11 attack?
BRENNAN: Their capability has been degraded significantly. We have taken off the battlefield the founding leader as well as other leading operatives. We have degraded their infrastructure. Their capability to train. Their capability to deploy operatives. So their capability has been degraded. Our defenses have increased. But that doesn't mean we can rest. And we're not going to rest until Al Qaida the organization is destroyed and is eliminated from areas in Afghanistan, Pakistan, Yemen, Africa and other areas. We're determined to do that.
STEPHANOPOULOS: Can you say one year out how much difference killing bin Laden made?
BRENNAN: I think it made a tremendous difference. It's taken away the founding leader of that organization who was symbolic -- a symbol of Al Qaida's sort of murderous agenda worldwide. And so, that has had I think a profound impact on the organization. And Mr. Zawahiri, who is his successor, is somebody who doesn't have the same sort of institutional support. He doesn't have the same charisma.
STEPHANOPOULOS: But he has taken more control than we expected, hasn't he?