  Resilience of most critical infrastructures against failure of elements that
appear insignificant is usually taken for granted. The World Airline Network
(WAN) is an infrastructure that reduces the geographical gap between societies,
both small and large, and brings forth economic gains. With the extensive use
of a publicly maintained data set that contains information about airports and
alternative connections between these airports, we empirically reveal that the
WAN is a redundant and resilient network for long distance air travel, but
otherwise breaks down completely due to removal of short and apparently
insignificant connections. These short range connections with moderate number
of passengers and alternate flights are the connections that keep remote parts
of the world accessible. It is surprising, insofar as there exists a highly
resilient and strongly connected core consisting of a small fraction of
airports (around 2.3%) together with an extremely fragile star-like periphery.
Yet, in spite of their relevance, more than 90% of the world airports are still
interconnected upon removal of this core. With standard and unconventional
removal measures we compare both empirical and topological perceptions for the
fragmentation of the world. We identify how the WAN is organized into different
classes of clusters based on the physical proximity of airports and analyze the
consequence of this fragmentation.
