Just to add to that a bit: early in this conflict there were airborne tankers flying in patterns near the border, along with V-22 Osprey aircraft. All with ADSB

Just to add to that a bit: early in this conflict there were airborne tankers flying in patterns near the border, along with V-22 Osprey aircraft. All with ADSB transponders on. Periodically the Ospreys would disappear from ADSB for a few hours and then return. No flight path to suggest they were landing somewhere, they just disappeared. The assumption by folks monitoring this stuff on twitter is that they were shutting off their transponders, going over the border into the Ukraine, and picking up US personnel (embassy staff likely). Then when they came back over the border they’d turn the transponder back on.