MacBook Air in the Western Flyer
This may not be a sanctioned use, but I've found that the backpack strap pocket on the Western Flyer is actually a great place to put a 13" MacBook Air inside a Vertical Cache. When you go through security, you just unzip the pocket, lift out the top flap of the Cache, and pull out the MB Air. Works well for me, and the extra padding on the back of the WF, combined with the Cache's padding, keeps the Air protected.
Of course, I know I could just get a horizontal Cache and put it in one of the WF's other compartments, but I use the Cache/MBA mostly with the Synapse, so the vertical orientation makes sense.