don't leave those on your key chain when you go to the airport!!
Why? According to the TSA, you can carry on up to a 7" screwdriver.
I don't know about you, but I think I could do more damage with a 6.5" screwdriver than I could do with a 2" blade pocketknife (which of course isn't allowed!)
Excuse the formatting - from the TSA website.
Item Carry-on Checked
Axes and Hatchets No Yes
Cattle Prods No Yes
Crowbars No Yes
Hammers No Yes
Drills and drill bits (including cordless portable power drills) No Yes
Saws (including cordless portable power saws) No Yes
Tools (greater than seven inches in length) No Yes
Tools (seven inches or less in length) Yes Yes
Screwdrivers (seven inches or less in length) Yes Yes
Wrenches and Pliers (seven inches or less in length) Yes Yes