How significant is air resistance for projectile motion?

Air resistance have some significant role in projectile motion if the motion lasts for some time.

Explanation:

Air resistance or air drag seems to be important in daily actvities and games like baseball. The trajectory of the projectile with or without air resistance or air drag is totally different. When we neglect air drag, the only acting force is gravity against the motion so the maximum height and range are suppose Hmax and R. Now, when we consider air drag, it is important to notice that there are two forces against the motion of the ball and along the direction of gravity. It seems that both maximum height and range are lesser Hmax'< Hmax and R'