A simple way to assess the hubbing level of an airport is to consider the share of connecting passengers in relation to the total number of passengers handled. A low level is related to a small airport with no connecting flights, simply acting as an origin and a destination. On the other side of the range, an airport with a high percentage (above 50%) of passengers connecting acts as an important hub in the air transport system. For instance, Atlanta is a major air hub (Delta Airlines), with more than half of the passengers using connecting flights to other locations.