Concrete suggestions: 1. Accept profiling as a legitimate tactic. 2. Open up the airports closed to general aviation post-9/11. 3. Reduce the time spent outside the secure area, partially for the convenience and efficient use of passenger's time, but more importantly to prevent the massing of people in a confined space, subject to attack by trivially prepared terrorists. You could do a signficant amount of damage in the average security line, and your preparation required would be measured in hours or days, not months/years. With a poison gas attack, you wouldn't even have to die yourself, though perhaps that misses the point for some terrorists?

Frankly, keeping the guns and knives confined to checked baggage, and making it possible to get from Boston to NYC door to door faster than the train, and you're on to something. I believe we've gotten to the point where we're exposing the travelling public to a higher rather than lower level of risk by the current security measures.