U.S. airports like this one in Los Angeles have further beefed up their security ahead of the September 11th anniversary.<br/> The move follows intelligence about a vehicle bomb plot focussing on Washington and New York City.<br/> Los Angeles International's drafted in extra police, bomb-sniffing dogs and bomb detection equipment.<br/> It was the scheduled destination for three of the four aircraft destroyed in the September 11th attacks in 2001.<br/> Passengers travelling just ahead of Sunday's anniversary said they hadn't considered changing their plans.<br/> SOUNDBITE: Katarina Papadakis, air traveller ,saying (English):<br/> "It comes for a minute, you think about it for a minute, but then you have to keep going, so no, then you have to stop thinking about this. If it happens it happens."<br/> SOUNDBITE: Mohammed Khattab, air traveller, saying (English):<br/> "Not all the time actually, just sometimes when there is extra security you start thinking about it more, but most of the time I just don't think about it."<br/> SOUNDBITE: Cody Campbell, air traveller, saying (English):<br/> "Never considered changing my plans. It always crosses my mind but I have full faith in all the security and all the precautions that we take now."<br/> A counter-terrorism official said the threat information came from Pakistan's tribal areas.<br/> Another U.S. official speaking anonymously said there was reason to believe the threat was linked to al Qaeda chief Ayman al-Zawahri.<br/> Paul Chapman, Reuters
