How far should authorities go to protect air travelers from terrorists?

The attempted attack on a Northwest flight to Detroit seems likely to prompt changes in security procedures. Getting on a plane may require more body scans and pat-downs. How far should authorities go to protect air travelers from terrorists?

Comments texted to MPR:

I think they should be more extreme in air travel from this scare. -Bob, Fargo, ND

I feel they should respect privacy but take security measures such as putting armed guards on the planes. -anonymous