Earlier I asked about whether or not the Co-Pilot would fit the new 11.6in MacBook Air (the answer seems to be 'yes'). I'm still pondering a purchase of the Co-Pilot. My other query about it is if the water bottle pocket can fit a vacuum mug (i.e., travel mug that holds hot liquids). If anyone has fit a vacuum mug in a Co-Pilot, please let me know what brand and size bottle you used.
As I posted elsewhere, I have not had a lot of luck with under-seat storage on planes lately. I'm still looking for the most compact travel bag that will fit into a fairly tight space. One important feature to me is the ability to hold a travel mug, which I use for drinking tea and coffee (much easier to hold during a bumpy flight than a styrofoam cup of liquid).