Hi, Roots, Don flies a lot for his business & as you know, he's a photog. too. He has it down to a science. He says for Dread to go to Thinktank.com, which is a company that makes bags. Check into the "Airport Security" & "Airport Check-in" bag grouping; he uses these exclusively & they are exactly within the airlines' exact dimensions. Basically, he stuffs a lot of things into his laptop case, which has a sleeve on the back that he slides onto the long handle for his rolling carryon, which serves as his camera bag, and into which he also stuffs a lot of extra things. On a few trips, he has even been known to get just a few clothing & toiletry items into one of these two bags & made it through a two-day trip just using these two bags!
Oh, and BTW, I believe that it's not 3.2 oz. for the toiletry items, but only 3 ozs.!