Here's a first draft compilation of the ideas expressed in this thread. Let me say that many Fters have contributed to this discussion and in similar ones in other forums, and that I regret that I am not able to acknowledge the originators of the suggestions since often several Fters have made the same or very similar suggestion. I do not in any way claim any credit for the ideas.

Many of these ideas seem to have already been implemented, or are being considered by the authorities. Others seem to have been implemented, and have been dropped (kiosk check-in, curbside check in to be allowed again).

A. Before Boarding

- No remote check-in
- Check passenger names vs. database of terroists
- Better trained/more professional security personnel
- Incentive bonuses for finding weapons by security
- Check-in only with verified ID
- Security check-in at the gate
- Security check for connections
- Only ticketed passengers allowed to proceed to gates
- Better screening during hire and better security checking of ground staff prior to entering airport
- Change airport security badges frequently

B. In the air

- Armed air or sky marshals on domestic flights and arriving international flights
- Self defense training for the crew
- Secure cockpits/reinforced doors/double doors
- Take control away from a pilot in the event of a hijacking via auto-pilot landings or ground control over-rides
- Armed pilots
- Resistence to be the new standard response to hijacking
- Pilots to de-pressurize passenger cabins if hijacked