First picture is Mike Haverly's first rack, for his Ranger P'up with raised canopy. It was made from 1" PVC pipe (smaller?), and worked very well for .40 sized planes. The rack was a little flexible, but was bungeed to the side of the truck, which stiffened it up ok. I may make something similar to fit my '06 Tacoma. A raised roof canopy sure would help, but the nominal 6' box is ok for .60 sized planes with the wing lengthwise. Mike's latest pvc rack locks into chocks on a plywood base in his Chevy 4-door Colorado...the planes fit diagonally, 'cause it's a pretty short box.
The next pictures are of the rack I made for my full sized GMC, with a cab height canopy. I wish I still had that truck. The rack will hold 3 .60 sized planes, as long as the spans fit within the pickup box width, which is ok for most designs. A smaller plane can fit under the other 3...Ringmaster or a Barnstormer, limit being distance between the wheel wells (4' plus a tad bit). I put a cargo bar across behind the planes and could put an ice chest and field box behind that. Note that the thing sorta collapses to store in the garage, and the two handles are only used to put the rack in and take it out, both with the planes. The planes did have to be slipped into the rack just ahead of the tailgate, but it worked very well. I had Rhinoliner on the pickup bed, and the rack didn't slide around, but it might be good to key it in place on the wheelwells, while you're at it.

Steve