I was at the Open House at J&P Cycles in Anamosa, Ia. a couple weeks ago. I talked with a representative of FLY motorcycle clothing about their open mesh jacket (the kind you can see light through). It had armor but when I asked how the mesh fabric would protect my skin in case of an unfortunate incident he stuttered and shuffled around and was clearly uncomfortable. He finally told me it would not give me the protection that a heavier jacket would. He then turned the subject back to how much air flowed through the jacket. I guess if I wanted to be completely cool while the flesh was being flayed from my bones by pavement this would be the jacket to buy!
I ended up buying myself and the Princess (fiancee) Fieldsheer Corsair Sport Jackets from Motorcycle Superstore. I immediately removed the liner and took it out for a test spin. It was still quite warm. I completely loosened all the Velcro adjustment straps it finally let some air flow through (especially the arms). I now ride with it just slightly zipped up and with the cuffs rolled back so air can flow up the arms. I have ridden in 95 degree heat and it was similar to wearing a heavy long sleeve denim shirt. Also, now that I have worn it a few times the fabric seems to be loosening up and allowing more airflow. Of course at stop lights I still lose about 3 pounds in water weight so now I have a water bottle holder mounted to the handlebars to handle that situation.
On a side note, I moved my bike from one part of my parking area to another the other day without wearing a helmet, jacket, boots or gloves. I was wearing shorts, a t-shirt and street shoes. Although I only moved it about 20 feet I felt naked and vulnerable in my own driveway! I don't see how these maroons fly down the interstate dressed that way.