I purchased two of these packs for a trip to the Alps. My partner and I used them for both plane and train travel as well as lightweight day packs. The Dry Isolation Pack is a handy little bag! It adjusts easily, is ultralight, packs down to the size of a tennis ball and the handles are thoughtfully wide enough so that if you weigh it down, it's still comfortable enough. However, the one drawback, we though was a major drawback: The fabric is so thin and lightweight, we didn't even make it a week into out 6 week trip before the bags had holes worn into them and failed to be at all "dry". I'd say it's a great choice if you know you are going to use it lightly.
Portland, OR and SLC, UT