How Airports Serve New Hampshire
Mark Pearson
This map displays the major airports in and around New Hampshire. It shows how the state can divided according to which airport is the closest as the crow flies.
The flags are a sample of 292 census tracts (of 292 tracts total) within the state.
Some census tract flags may look like they are colored for one airport's region but are actually in another airport's region. The census tract flags are colored with which airport they are closest to as the crow flies along the surface of the earth (the Haversine distance formula). The region boundaries that are displayed on map were computed assuming assuming the earth is flat. (The lines that divide regions are a Voronoi diagram, and I couldn't find any algorithm that calculate the lines on a sphere such as the earth.) In short, although a few census tracts may look like they're mislabeled near a boundary, it's actually the boundary that is slightly wrong.
For more information, see the full report:
http://www.mark-pearson.com/airport-distances/

MHT serves 1,196,948 people in NH
Manchester-Boston Regional Airport

PWM serves 70,244 people in NH
Portland International Jetport

BTV serves 49,278 people in NH
Burlington International Airport

dividing line

2,966 people
closest airport: MHT

2,938 people
closest airport: BTV

4,144 people
closest airport: MHT

closest airport: MHT

closest airport: PWM

closest airport: BTV