In fact, knowing the moment photo was taken from EXIF, there was no need to "plot the line". They could point the exact location by using orientation of the sta

In fact, knowing the moment photo was taken from EXIF, there was no need to "plot the line". They could point the exact location by using orientation of the stars - stellar time (assuming the horizon is level which, in the airfield, is a very very good assumption to make). Procedure is as follows: Right ascension of the culminating star ("celestial longitude", taken from the star catalog/star map, of any star which is right above the celestial pole/"Polar star"), is the stellar time. Knowing date (from EXIF), you get local solar time (which is equal to the stellar time on the spring solstice day, then makes a 24 hour loop over the year). Difference between local time found this way and UTC time (taken from EXIF), gives longitude, because the Earth is round. If EXIF does not contain the time zone, that gives 3 points in the U.S., one for each time zone, but it must be super easy to pick one. But most probably, EXIF contains the time zone.