The only two things that worked
Chechen terrorists did it in 2004. I said this in an interview with then TSA head Kip Hawley in 2007:
I don’t want to even think about how much C4 I can strap to my legs and walk through your magnetometers.
And what sort of magical thinking is behind the rumored TSA rule about keeping passengers seated during the last hour of flight? Do we really think the terrorist won’t think of blowing up their improvised explosive devices during the first hour of flight?
From schneier.com:
For years I’ve been saying this:
Only two things have made flying safer [since 9/11]: the reinforcement of cockpit doors, and the fact that passengers know now to resist hijackers.
This week, the second one worked over Detroit. Security succeeded.
EDITED TO ADD (12/26): Only one carry on? No electronics for the first hour of flight? I wish that, just once, some terrorist would try something that you can only foil by upgrading the passengers to first class and giving them free drinks.
the reinforcement of cockpit doors, and the fact that passengers know now to resist hijackers.
