I don't really want to argue semantics, but a projectile is a body for which the only force acting upon it is gravity. Ergo, the drag specifically makes it NOT a projectile motion problem.
Some of the technical posts in this thread:
http://www.chiefdelphi.com/forums/sh...d.php?t=124222 might be helpful to those who would like to model more of the physics. As noted in that thread, whether or not drag is significant is a judgement call and very much depends on the velocities involved.