Until pictures of the new Aeronaut in other colors make it to its product page, the blog post about the newly back in stock Smart Alec is probably the easiest way to select and compare colors. Each of the five initial color offerings for the Aeronaut (Crimson, Black, Sage, Kiwi, and Steel) is shown on that page. Having all the colors up at once makes comparisons easier, in case you want to know, for instance, how much greener sage is than steel.
I'd also like to point out that the LUX bag packs really well into the central section of the Aeronaut. In flattened form, it almost exactly matches this compartment, and provides a contrasting background similar to what you have in other Bihn bags. The bottom of the interior to the main compartment of the Aeronaut otherwise has a black (200 denier) nylon lining with a grid of white lines (somewhat like a quadrille-ruled pad of graph paper). The same material is used around the borders of the zippered mesh pocket on the underside of the top flap. This can be viewed in the picture at the imagometrics review site if you pause the browser animation showing the fully packed Aeronaut in the "opened" position -- the pattern can be seen in the thin strips on the left and right sides of the underside of the open flap. Similar lining is used on the right and left sides of the main compartment.
Anyway, with the LUX bag packed at the bottom, I get the same contrasting crimson color of the outer Aeronaut in the interior. Very handy if you will be needing another bag at your destination, or for use at a meeting where you are picking up other material as described in this post, since the LUX bag has a larger holding capacity than the large cafe bag, yet probably packs flatter. When traveling by air, I agree that you probably want to carry your laptop in a second bag (Brain Cell, ID bag, Buzz, Smart Alec, etc.) that is reinforced and more accessible for inspection.