Expert: Mark Janus - 5/14/2007

Question
does the a/c engine sucks the air ahead of it and create low pressure ahead of it and therefore able to advance ahead OR by thrusting the air back and advances forward like a jet plane.

Answer
By a/c I'm guessing you mean propeller aircraft....  actually whether a propeller or a jet is used, both change the momentum of the fluid. Half of that change in momentum occurs at the  rotor disk for a propeller so the other half of change in momentum occurs in front of and behind the propeller (due to the pressure differences created by the propeller)...