Just go out and try to ride your bicycle fast if you doubt aerodynamics.
Or heck take all the fairings off your motorcycle and sit up straight and see what it feels like at 100mph.
If you look at some of the websites/forums for people who are obsessed with gas mileage you'll see some freaked out econocars which have had massive aero work and they get close to achieving 100mpg, etc.. but they look like something out of a sci fi movie.. it really is all in the aerodynamics.
http://forum.ecomodder.com/showthrea...90.html?p=2110
I think that's been posted before here.