I have been enjoying
this site over the last few days. It's a flight tracking site and if you click on the square with 'U' on it at the top of the map, you filter for military flights.
There has been an almost constant presence of airborne early warning, ground radar, electronic intelligence and tanker aircraft pootling near the Poland-Ukraine border. You sometimes seen surveillance drones appear and disappear and special forces helicopters out on trips. You can only see aircraft that have their beacons on and of course any enemy can see the same. There's a clear message to Russia that NATO is watching...