Sorry for chiming in late...

I think a better way to illustrate this concept being discussed here is to use a boat on a flowing river (with no wind, only the flowing water) instead of an airplane in invisible air. A lot of people can visualize this scenario in their heads more easily than they can with an airplane. Two different modes of transportation, but the exact same principles of physics...

To show the relative motion relationship, have them magine driving the boat in a circle around a leaf floating in the water... and how their track relative to the bank differs with their track relative to the leaf... I get the "Ahhh, I get it" a lot faster with the boat example than with the airplane. People in general are more familiar with how a boat behaves in water than they are with how an airplane behaves in air... it is a more tangible example for them to grasp. The physics of the 2 are the same.