At 22 seconden u will see an aero fly into a green Orb and disappear. Here will learn that they communicate while in flight; because u witness the green Orb blinks in preparation for the incoming aero.
See the red driehoek that the aeros have placed in the cloud. Notice how the wolk housing the driehoek is much darker than the surrounding clouds. See meer at www.youtube.com/aerostockians