Items will be filling that space so they won't be flying around, they'll be penned in. The edging does a pretty good job of holding things pushed up against them. Heavier items that slide around sometimes bump over the edge. However for most of my travel this space will be filled with suitcases, and other items up to the sides of the cargo area (which is why I made the edging flexible so I can put items on top of it if necessary). The totes you see on top now will actually ride in the rocket box, except the tall blue one which may get left behind because it's just too big.

For working around town after I've arrived at my destination, most tool and equipment items will be stashed below, clothes and suitcases will be moved into the hotel room, leaving the platform vacant. It then serves as a workbench which will stay mostly vacant except when I am assembling something there, drilling, etc.