airports? it has to be a multi-layer of security against all kinds of threats. foreign and domestic. >> until they figure this out. give us a sense of what was happening at sea-tac airport. the officials, the tower, the ground team realize that a plane is taxiing and could be taking off. what would they do to try to prevent it? >> very little they could do. we've all seen in hollywood stunt movies where they surround the taxiing plane with trucks and fuel trucks and try to stop it from taking off. in reality, if this person was moving the plane. if they were or were not authorized to taxi the plane and how they got access to the plane alone without someone else. but once a person's taxiing and heading on to the runway, very little you can do to stop a plane from taking off. they're going to go. once they rev the engine and they're going down the runway, they're going.