How does wind illustrate that gases are fluids?

Answer 1

Study of mass flow tells us that gas and fluid flows are the same. It's all about turbulence, pipe wall resistance, kinetic energy, etc

Answer 2

Wind , like other gases, flows when it is subjected to a pressure difference. Large pressure differences or gradients create
faster wind flows. Hurricane Katrina was so strong because
there was a tremendous pressure gradient.

Both gases and liquids are fluids since they will flow if there is a pressure difference and flow is not restrained.

I hope this is helpful.