http://gc.kls2.com/cgi-bin/gc?PATH=C...TH-COLOR=red&P ATH-UNITS=mi&RANGE-STYLE=best&RANGE-COLOR=navy&MAP-STYLE=
to find approximate miles using 3 letter airport code, use this site.
it takes the latitudes and longitudes and calculate the great circle distance, within a couple percents with the airlines' own definition