I assume your S&S case is the hard case.
One more bag option that you can wear as a backpack that was so obvious I did not even think of it is the S&S Backpack case, the black bag pictured in my photos in my previous post. Price would be a bit more than the others, but it also collapses in size and would fit in an S&S hard case for storage.
I have worn it as a backpack with a bike in it and packed to 49 pounds a couple of times. It carries well enough, no worse than the SealLine bag.
I cut two pieces of Coroplast to put in the sides of my S&S Backpack case, 26 X 26 inches with rounded corners to make my case a bit stiffer and give it better structure. I do not want to crease the Coroplast sheets to fold them, but if I chose to do that they would still work fine when unfolded and used in the case.
There are four side pieces in the S&S Backpack case that are held together in the corners with velcro. I am guessing that those side pieces are about 29 or 30 X 10 when flat. Thus, the S&S Backpack can be packed inside the hard S&S case. The side pieces are flexible for packing, but are not too flexible, they provide adequate support to the assembled case. I find that assembling the Backpack case works best if the velcro straps in the corners is left a bit loose.
Photo below is my Backpack Case with the side pieces removed and stored as flat sheets inside the case, I also have my orange Sealline backpack in the case in the photo, thus the bag is much thinner than 10 inches, this is how I stored it in the luggage room at a hostel on two trips.
If I wanted to fold my Coroplast sheets, it would be even smaller.
Advantage of this would be that if your other S&S case was damaged, the S&S Backpack case could be a contingency to use for the bike.
I mentioned the Ritchey case in my previous post, that case is slightly over 62 inches by the way that airlines measure. But the Ritchey owners I have talked to almost never are charged an oversize fee. And since some of the airlines no longer charge that fee, that is even less of an issue now.
The photo below is my bike inside the S&S Backpack case, without racks (do not fit) and a few other things to lower the weight to 49 pounds. I made a DIY center support for the case out of two wood dowels and two small sheets of plywood, you can see the plywood sheet on top of the bike, there are two screws in it to hold the pieces together. I really wanted to make sure that the airlines to not crush things. My first center support was masonite and that was cracked after a trip, so I replaced with thin plywood instead. Since the masonite was cracked, that did its job well without damage to the bike.
