Just as with a lot of other survival equipment... You leave it in the aircraft.
If that's impossible, what you need to realize is that security is not so much there to prevent you from taking stuff in your own aircraft, but from you handing stuff to somebody else in the terminal, and that person then embarking as passenger on a commercial flight.
So airports should have procedures in place to either escort you, with your dangerous goods, to your own aircraft, or for temporarily confiscating the stuff and then deliver it to you when you're on board. But to be honest, I can imagine that security departments would like to keep these exceptions a secret, since they're very resource-intensive.
Talking about this... How does security prevent you from bringing dangerous goods into the terminal, from airside, assuming you just flew in from a grass strip into an international airport? If they did this properly, they would check you before entering the terminal from airside and thus again you'd not be able to take the knife with you landside. So you would have no choice but to leave it in the aircraft.
In any case, the flight we're discussing here was in Canada somewhere in arctic conditions. I don't know the exact rules, but I believe for those sorts of flights Canada *requires* you to carry a rifle, so you can keep the bears away in case of an emergency landing. I don't think security there would be having a problem with a rescue knife.
Last edited by BackPacker; 12th December 2008 at 09:18.