I hauled my planes in pickups with shells for 19 years.....I made a plywood shelf, supported on each side by the top of the bed/bottom of the shell, and running from the front to about 2 feet from the tailgate. Carpet it. Carry the planes on this, with the heavy stuff (tool boxes, starter box, gas, lawn chairs, ice chests, etc. on the bed of the truck below the shelf.

You can use a piece of 1/4" plywood, mount wheel chocks on each end of it, and rubber band the gear to this base so the plane can't hop out on bumps. Then put a piece of Velcro on the bottom of this plywood base, and it will not slide when you hit the brakes.

Makes a neat way to transport our planes. But I like my Ford Explorer better, with the seats down!