I put some Anco winter blades on my car and I too, couldn't get the airfoil over. Initially, I did notice a difference at speeds > 35mph, that the blade didn't "stick" to the window quite as well. So it would seem the airfoil serves a purpose aside from aesthetics.
I've also noted that the driver's blade doesn't meet the windshield at about the point where it intersects the passenger blade. So far it's not a huge issue w/ regards to my field of vision, but as the roads get sloppier here from snow / slush / mud, it may be.
I'm planning on throwing the airfoil blade back on in the spring, and then hit my MINI dealer for a free replacement blade (I think they're covered?)