The A-380 has beat out the Boeing 747 as a target by International Terrorists. The A-380 will become the largest passenger jet in the world holding the largest number of passengers. If and when an International Terrorist Cell gets one, it will become instantly the largest airline disaster in the history of the world, due to the shear number of passengers on board. Luckily bringing down such a large aircraft will not be easy, nor will it be able to be blown out of the sky with a handheld anti-aircraft missile unless it is lucky enough to hit a fuel tank. This of course is unlikely because most handheld missiles are heat seeking and therefore will generally go to where the heat is instead, thus taking out one of four engines.

The A-380 in most of the configurations currently being advertised seems to be able to hold nearly 40% more people. This is why the International Terrorist Cells may target it. Airbus is putting countermeasures for anti-aircraft missiles as an option for those airlines, which order them. The A-380 is quite a bit bigger than the 747 as you can see:

http://www.flickr.com/photos/mccreath/11209056/

Many airports cannot even take an airliner so large, as the distance to turn it around are significant and the wing tips are wider than that of the runway, meaning the wing tip vortices will dig up the grass on the sides of the runways making ditches on both sides. Think about this.