While I was watching the realistic movie The Castaway (Tom Hanks) I thought what can be legally carried on one's person when flying these days on major Airlines?

Obviously, anything sharp or a blade is definetly out, as are probablly H2o proof Matches, but could I bring a 2" long Flint Striker attached on my key ring on board a jet airliner? It's quite small with a tiny faded orange mini handle, the whole thing might be 3" long and it's very thin. I wish I could make a key outa' Flint!

But seriously, what types of Survival items can be carried on one's person that would legally pass thru an airport X-ray machine?

In the movie, when he lost the Survival bag attached to the raft, you knew he was kinda F*&*&* ed.