The flying clouds represent the element Air. Air is not one of the traditional five Chinese classical elements. Nevertheless, the ancient Chinese concept of Qi or chi is believed to be close to that of air. Qi is believed to be part of every living thing that exists, as a kind of "life force" or "spiritual energy." That's the reason it is set apart from the elements as superior. The ancients could see that air was a vital force in the breath, and linked it with movement, even giving the status of 'spirit'.
The ancient Chinese described qi as "life force". They believed it permeated everything and linked their surroundings together. Qi was also linked to the flow of energy around and through the body, forming a cohesive functioning unit. By understanding the rhythm and flow of qi, they believed they could guide exercises and treatments to provide stability and longevity.