Plane was the test bed for the military application in my citation, the ground station could be ground or roof mounted and camouflaged. As it would emit no RF, you would have to know where to look for it to find it (unlike say, StarLink ground terminals, which are detectable).

If you emit RF in a contested environment as a civilian, you can be found using multilateration (for this context, I assume if you have military comms equipment, you have access to exotic RF that will make this difficult similar to have quick and saturn). SDR networks on the public internet enable this today, as long as there are enough receivers online in an area and you know what you're looking for, so I don't think it's beyond the grasp of nation state actors.

TDOA Transmitter Localization with RTL-SDRs - https://panoradio-sdr.de/tdoa-transmitter-localization-with-... - July 17th, 2017