This is my go-to bag for air travel (I fly about 100,000-150,000 miles a year).  It's big enough to carry bulky items, has the right pockets in the right places, and is pretty comfortable to carry as a messenger bag.  Fits under the seat of all planes (sometimes I have to turn it sideways to get it partially under the seat in smaller planes), and has never let me down.  Love it.