Traveling with a CPAP, one of the bulkiest parts is the hose--there are smaller, more compact CPAPs for travel but hoses have stayed bulky. I recently found one that packs down better, though. I tried it on my last trip and it was good, so I recommend it. The 6 foot Collapsible Travel CPAP Hose is basically a tube of thin plastic (like a thick Ziploc bag) with a coiled wire in it to give it some shape. For packing, it collapses down to a little smaller than a paper towel tube--in fact I put it inside a paper towel tube to give it a little extra protection in my suitcase. It fit nicely at one side of my A45, filling some space at the edge that might not have been used otherwise.
It feels a little flimsy, so I wouldn't recommend this to replace your CPAP hose for everyday use at home, but I'm happy with it for travel. I suggest taking along a small roll of tape in case you need to make any middle-of-the-night repairs. (I got that idea from a friend whose cat used to attack his CPAP hose in the middle of the night. He told me he keeps a roll of electrical tape by his bed now so if his cat punctures the hose, he can patch the hole and go back to sleep!)
If you have any favorite tips for CPAP travel, I'd be glad to hear them--please share them here.