What does this indicator measure?

In an era of global business, connectivity is taking on increasing importance.  Frequent service to a variety of destinations facilitates face-to-face contact with business in other cities, attracts new firms to a metro area, and stimulates employment in existing firms.  An airport’s position in the air travel network has pervasive effects on metro employment growth, and the relationship is causal (meaning connectivity itself drives employment growth).  Below we present information on air connectivity with the number of destinations served by metro area airports.–explanation courtesy of the Brookings Institute

The indicator is presented for the Syracuse, Albany, Buffalo, and Rochester Metropolitan Statistical Areas (MSA’s), and dates from 2009.