There are several kind of air-splints. There's the "air-cast" that most ER's use when you have an ankle sprain. Basically, 2 pieces of plastic connected by a piece of hard cloth under your heel. There's the real "air" splint, basically a piece of plastic with numerous tubes that roll around an extremity and immobilize it - http://galls.com/style.html?assort=general_catalog&style=SI725
Then there's the vacuum splint, kind of plastic filled with beads. You wrap the fracture, pull the air out, and it hardens, due to the beads being forced together- http://galls.com/style.html?assort=general_catalog&style=SI747 This seems to me most stable, and theoretically you could move the entire limb as a unit. I don't think it's strong enough to weight bear on, but as fractures go, it might be most comfortable and stable. Then again, good old cardboard and some towels can be pretty stable too if done properly.

MoBob, I don't really think there's much difference in CPR masks, except: pocket size, or keychain size. Keychain is essentially a piece of plastic with a small valve in it (of various designs). I guess this would be a "one size fits all" more than the other. The pocket size is kind of like the size of an Ambu-bag mask, but folds. You can technically use this kind on a child by flipping it backwards, so that the nose portion is over the chin, and the large part over the nose. You still get some air leakage around the chin, but you're not going to gouge the eyes out with the nose piece being too high up.

As for which is "safer," I have no idea. I carry both, never used either (on or off the job)