i ended up carrying the aeronaut and ruck's sac on my trip to india, and this worked out quite well. the ruck's sac only came along as a last minute decision was made for me to carry my macbook inside a soft cell inside the ruck's sac. but i'm glad i brought it because i packed everything i needed in-flight and in-train in the ruck's sac and left the rest of the stuff in the aeronaut (even though i didn't check in the aeronaut).
i also carried my liquids and other bathroom items inside of a clear quarter packing cube, and i was able to put this through the security screenings at washington dulles, and paris charles de gaulle airport without needing to move the liquids into a separate ziplock bag.
inside the aeronaut was a packing cube backpack. this worked out really well, because i did a little shopping while i was in india :). so i checked in the aeronaut on my way back, and i carried the packing cube backpack and the ruck's sac as my carry-on's.
by the way, the aeronaut doesn't look the same. functionally, it's still perfect - but it looks beaten up and stained. it's sad what airline travel does to your bags.
pictured below is the red aeronaut and blue ruck's sac sitting on top of it. as you can see, they fit nicely in the overhead storage area you are provided in the shatabdi express. i guess that doesn't mean an awful lot - people put big 30" suitcases up there. it's a scary accident waiting to happen, though - because if the weight is not properly distributed, the bag can come crashing down. you don't have to worry about that with the aeronaut, however, which fits nicely on that storage rack.
sorry for the poor picture quality. the only camera i had was the one built into my iphone.