Edited for: My bad. NO LONGER TRUE!!! TSA said they were going to and then back off. As Joel's link below shows, the newer website postings are in agreement – No knives, snakes, or bombs on planes. I'm back to gnawing up plastic wrapping and filing my fingernails on a rock.
My original post:
In Alaska, we are REQUIRED to board planes with .44 magnum, a requirement which is only waived if, instead, you have a 12-gauge with rifled slugs. But for the rest of you:
For the last two months, you've been able to carry a pen knife through security and onto a plane. The rules are:
The blade must be shorter than 2.36 inches.
The blade must have a width thinner than ½ inch.
The knife cannot have a locking mechanism or fixed blade.
The knife cannot have a molded grip.
Here's a site that has links to photos of allowed and disallowed knives:
http://www.knife-depot.com/knife-information-100.html
Punchline: a SAK Classic is fine and well within the rules.
Gram-weenies should focus on the "cannot have a molded grip" criteria and look at the photos. Some of those Sypderco knives have what I would consider "molded grips".
Somehow, after the Grand Canyon R2R2R, I ended up with a padded envelope that Game Warden Mike Moore had mailed to Death-run Orgainzer Eugene Smith with his tiny little SAK knife in it. 13 months later, and he could have carried it on board himself.
I have NOT found a reference on razor blades. I'll be trying with one of my SAK Classics in 26 hours. You're welcome to do your own tests.

