I really like this bag, it is very roomy, very small carry on, doesn't fit too well under the seat, but probably could if it were not filled totally.  But then you'd have no feet room on a plane.  I can get my electronics, and 2 nights of changes of clothing, plus all my hair, face, contact stuff.  Great for a 2 night stay somewhere.  Does not have a back strap to mount on another suitcase, so I got the ONSON Bag Bungee, and that worked well.  I just need a bag that has a long enough handle to use the bungee with.