Hi and thanks for your help earlier! Would the answer to this question ...

How is the flow of air used in transportation.

would the answer be....

When a fluid flows past a body it exerts a force on it.

2 answers

The low of air over the wing of an airplane or the blade of a helicopter produces an upward force
The low pressure of air over the wing of an airplane or the blade of a helicopter produces an upward force.

http://www.mansfieldct.org/schools/MMS/staff/hand/flightpressureonawing.htm

I hope this helps a little more.