airport_distance: Calculate great circle distance between two airports
Description
A function that calculates distances between pairs of airport codes. Distances are calculated using the Haversine formula which assumes a spherical earth. Distances are returned in kilometres.
Usage
airport_distance(airport1, airport2)
Arguments
airport1
Takes a three-letter IATA code corresponding to an airport
airport2
As above
Value
The great circle distance in kilometres between the two airports