I've also used the large flat "gift wrap" and under bed storage Rubbermaid plastic box/bins but they are often limiting to what I can get in them.
Here is a really simple to make, Nesting Up-right standing carrier/display rack I developed for my own Van but seems to work well in other folks SUV's and larger vehicles.
They are each made from a cheap 1"x 3" or 1" x 4" x 8 foot long lumber, 1/2" dia hardwood dowels, a few wood screws, and 2 10-24 machine screws with washers and wing nuts.
With the addition of some spent 18 & 24mm motor casings these 8 rocket racks can handle just about any size model with a motor mount. Racks can be carried loaded in almost any position and have holes in the flip out feet for Tent Stakes to prevent wind turnovers outdoors.
I made up 10 of these racks back in 89-90 for transporting my fleet to large launch and demos almost blanketing a 5 square foot section of the van bed. Sure made loading and unloading a snap eliminating Broken fins and bent tubes
. On the field that can be interlocks with eachother with the outside 4 feet staked down that will servive the worst Gusts and winds without a problem.
Since then I've made and given away about another dozen to flying friends and guys in the club. Some who only drive cars but like to use the stands out of the field.
Hope they or something similar helps in your transport needs.