Military planes often deliberately have them on; not every mission is secretive. You can often see NATO planes on FlightAware in the Black Sea clearly keeping an eye on the Ukraine theatre.

Example: https://flightaware.com/live/flight/FORTE10/history/20230821...

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adastra22 20 hours ago | parent | next [-]

I was speaking perhaps too casually, but "military things" was meant to mean offensive operations. The kind of things where you might expect to be fired upon (or at least need to take precautions against that happening). A transponder is a homing beacon for missiles.

	▲	isodev 19 hours ago \| parent [-]
		You watch too many movies, there are plenty of other things for the missiles to track. Transponder in civilian airspace is just how you keep planes from crashing into each other.

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FireBeyond 21 hours ago | parent | prev [-]

And they often deliberately have them off, even for training flights, at least looking at my ADS-B receivers raw output and correlating to FA/FR24/etc.

	▲	ceejayoz 16 hours ago \| parent [-]
		Yes? I’m contesting the “always” bit, nothing more.