I’d go with the plastic version of the Crateworks box. It looks expensive on the face of it for what’s basically a glorified box made from a sort of plastic corrugated cardboard alternative, but it’s brilliantly thought out, impressively tough in all directions and designed so that the bike is really well protected. I’ve used padded bags for years, but I’ve borrowed a friend’s Crateworks box several times to fly with my road bike and would happily buy my own as a result.
They also fold down for storage, small enough to live in a T5 camper for a fortnight without being excessively intrusive.
I don’t think the issue with bike damage is how it goes up the ramp, it’s when it gets other luggage dumped on top of it, gets flying around out of sight by baggage handlers etc.