What the other solutions fail to mention is that you actually have to use your binoculars on Han to initiate his movement and bring up the next waypoint.
Once you’ve reached the first checkpoint, wait until Han lands and watch him with your binoculars. As you watch him, he’ll enter a jeep and start driving away. A new checkpoint will then be placed on a ridgeline to your left, proceed over to it and repeat with the binoculars. Keep tracking him until the next waypoint appears. Proceed down the hill and past the two enemies on your left to the next waypoint.
The next waypoint Han will actually approach, so just stay back a little and wait for him to leave. Either silently kill or sneak past the enemy sniper inside the bunker and continue following the waypoints to reach the last checkpoint. Kill the two enemy snipers and await your orders to call in an airstrike. Do so when Han is inside the radio station and the achievement is yours.