Looking at airport security, it appears that if there is another major incident, we'll be back to the same complaints as after 9/11. After 9/11 there were complaints about poorly paid, poorly educated contract workers doing the security checks. Passing through an airport checkpoint yesterday, the ID check was not being done by a TSA officer, instead an employee of a private firm was checking security. And looking at the TSA employees, I'm not sure how much better the workers are.
The irony is that according to the 9/11 commission report, several 9/11 hijackers were flagged by airport security. However, the only response at the time was to search their luggage. The system wasn't setup to stop suicide attacks. If it were, the much maligned security company employees would have at minimum reduced the number of hijackers on the planes.
However, given the higher awareness of commercial aircraft security, the next attack will most likely come from some other direction.