Carpet bags are made on frames which allow them to open wide and appear cavernous.
They make ideal overnight bags with a difference.
I have a carpet style handbag which I use when I go on holiday as a cabin bag. i don't like to have to carry too much stuff around when browsing the shops at the airport but I do need something which will hold my money, passport, camera, cardigan, laptop and maybe a magazine. My 12" carpet style handbag does all that perfectly and still fits under the seat in front. It also closes securely and sits under my arm with the straps over my shoulder.
As well as bags currently available to buy, this page also gives a brief history of carpetbags and how they came about.