To store heavy bicycles inside our hatchback, I designed a tray that slides over the folded-down seatbacks. When slid to the outside, our 58 and 52 pound electric bicycles can be easily loaded from the side onto the tray (both bicycles are BEVs). We both agree that tilting the bikes over onto the tray is far less strenuous than lifting them onto a rear-mounted bicycle rack as the total lifting height is much lower: And then the tray is simply slid into the hatchback so that the bicycle is completely inside: The tray is two laminated layers of 1/4" plywood plus two wooden wedges sandwiched on the left and right side to which the handle is attached by 6 wood screws. I also screwed a sheet of aluminum roof flashing to the bottom of the tray in order to make it slide more easily over the carpet and seatbacks. Besides bicycles, this tray would make loading heavy, bulky, or awkward items inside a hatchback easier, as long as such objects will fit through the hatchback opening! Storing our bikes inside keeps the aerodynamics of the Prius clean and the bicycles safely locked inside and out of the weather whilst in transit, both of which we value on long trips. Cheers!
The final test was fitting both of our ebikes on the tray and sliding it inside. We had to remove the front wheels and then carefully overlap the two bikes on the tray whilst it was extended in back of the car: Then pushing the tray inside with the combined weight of 110 pounds of ebikes was fairly easy--having the bottom covered in aluminum rood flashing to reduce the friction turned out to be absolutely necessary, though. As you can see, the quick-release front wheels are just inserted wherever there is space in this somewhat awkward bicycle sandwich. But now we are ready to take on bicycle routes all over the USA and Canada ! Cheers!