Will BILLY Bookcase, white, 31 1/2x11x79 1/2 " fit in a Citroen C5 Aircross 2021?

The C5 Aircross gives you a wide, square loading mouth: 41″ across and 30¾″ tall, with a floor that is actually wider than the opening at 41¾″ between the arches. Seats up you get 38¼″ of length; folding them stretches that to 67¾″, a gain of 29½″. The catch is the sill, which sits 29⅛″ off the ground, though the floor drops only 1⅝″ behind it, so boxes slide in level rather than falling in. Wide flat packs do well here; very long ones run out of floor before they run out of mouth. Lift heavy boxes to sill height first, rest them, then push.

The BILLY ships as one long, flat carton, 81¼″ × 11¾″ × 5″, and it is heavier than it looks at 88 lb 1 oz. The shape is the awkward part: long and only 5″ thick, a rigid panel box that will not bend or fold around a wheel arch. That length rules out most boots with the seats up. You want an estate, a hatchback with the rear seats folded, or an SUV that gives a flat run past the front seats. Two people make this easy. Carry it on edge, slide it in low, and rest the leading edge on something soft.