Two things have done more than TSA to keep airplanes safe:
1. Hardening cockpit doors and policies that keep travelers away from the cockpit.
2. Travelers fight. Both the Shoe Bomber and the Underwear Bomber were discovered and foiled by travelers who have learned that resistance is the difference between life and death.
Frankly, TSA could be replaced by private security firms today and air security would not significantly change.
1. Hardening cockpit doors and policies that keep travelers away from the cockpit.
2. Travelers fight. Both the Shoe Bomber and the Underwear Bomber were discovered and foiled by travelers who have learned that resistance is the difference between life and death.
Frankly, TSA could be replaced by private security firms today and air security would not significantly change.