You are head of the FBI Counter-Intelligence Unit. Six months from now you get a credible report (human itelligence agent) that a cadre of blue persons (substitute for "blue" any reasonably unique looking subset of the population, whether by ethnicity, size, sex, etc.) have been trained as pilots. Further, they have been trained to carry, in their bodily cavity, a knife of substantial size made from a material which is not presently detectable by automated equipment. They intend, within the next two years, to stage an incident similar to what just occurred. Apart from any changes in the aircraft (heavier doors on cockpit, etc.), as it applies to screening:

1. Do you increase scrutiny of blue people?

2. Do you begin routine examination of bodily cavities?

3. Do you ground all aircraft in the US?

4. What do you do to screening?