“Plane spotters do this all the time.”
At US Air Force bases?
Military aircraft also use civilian airports. Lots of plane spotters there.
Oh yes, at bases. And don’t forget, a huge majority of Air Force bases share a runway with a local civil airport.
And transports are prime candidates for such sharing.
Yup. Same as at airports. They find a location close enough to observe the comings and goings but not breaching the fence. Hell, there are several locations near Kirtland AFB in Albuquerque that are closer to the flight line, but outside the wire, than many locations on base.