Look at that Thorn Nomad and how well it fits into the case. 26" has its perks. I use the same backpack case with my 58cm 700c tourer. Not only is the bike larger than average, but it's a touring bike so the fork steerer is extra long. Once upon a time I used to pack the bike with the tires on the rim; bottle cages, brakes, and crankset on the frame; but jigsawing all that into the case took 45 minutes every time and everything was so weaved together that I was worrying about my wheels not staying true. These days I take the pedals, crankset, bottle cages, tires, and brakes off before packing the bike. I have dynamo lights so the rear light cable has to come off the frame, and the front light dangles between the fork legs in the case. The fenders stack around the rims. The tires get folded and shoved somewhere. The saddle and front rack all fit in the case. The rear rack has to be packed separate. I use a 100L mountaineering duffle to hold three panniers, the rack, and my helmet. I take my fourth pannier and handlebar bag as carry-ons. The bike bag weighs 16kg. The duffle weighs 18-21kg depending on touring load out. The international weight limit is two pieces of max 20kg each. The counter clerks don't bother you if you're a couple of kg over.

Let me summarize: it's not just a bit of extra work to pack one of these bikes. Unless you ride a frame size below 54cm it's like you're building a new frame every time. You will need to tour with the coupling spanner and possibly a crank/bottom bracket tool. If you are going on a week long tour, you are going through the process four times in the same week! What usually ends up happening is that by the time I get back from my tour, I'm so drained from working on the bike that I leave it in the case for weeks and just ride one of my other bikes. Eventually I put it back together because I need it for hauling something, as none of my other bikes have racks.

I live in China and the airlines here don't charge for bikes. Unless I'm flying international I just use a full sized bike bag. I've flown enough international with the bike that I've made my money back, but it's taken years.

The couplings add a small amount of weight to the frame. Once tightened to spec they are as strong as the tubes and do not affect the handling in any way whatsoever.