There are simple ways to get more into your carry-on.
If you need to contain it, there is a product for it in the travel section at the container store.
There are items to contain perfume, power cords and your bathing suit.
There is a bag that can fold up compactly, but when you are ready to come back with souvenirs it unfolds to a large bag.
A zip lock space bag promises twice the storage. You fill and roll out the air to make it even more compact.
Eagle compression packing cubes have a compression zipper. We packed four cubes in one carry- on and there was tons of room to spare.
How to get the most out of your carry-on