I fitted my Nomad Mk II, size 590M into the S&S Backpack case, but it was not easy. Thorn says the fork won't fit, but it worked for me.
http://thorncyclesforum.co.uk/index.php?topic=13407.0Perhaps it will fit in a Ritchey Break Away case? The Ritchey case is slightly larger than the 62 inch criteria that most USA airlines use, I am in USA so I am unable to speak about airline criteria outside USA.
Most of the Ritchey owners that I have talked to said that the airlines did not charge them for being oversize, but on one occasion one Ritchey owner said he had to pay the oversize fee. I think airlines are much more concerned about weight, their scale tells them immediately if they should charge an overweight fee. But I have never seen an airline employee take out a tape measure.
You will see a lot of references on the internet to Ritchey Break Away bikes as fitting into a case that does not incur the oversize fee, even though the case is slightly oversize.
I have a Break Away, but I bought it shortly before Covid. And I have only flown once since Covid, have not yet had a chance to fly with it. But I usually fly Delta in USA, they have now canceled their oversize fee for bikes, so the airline would have no reason to measure the case size.