No, scanners and TSA agents stop weapons from being brought on board by catching thousands of guns per year and 10's of thousands of knives. The fact that would be terrorists now KNOW they can't get these on board because of the scanning, TSA pat downs, no-fly lists, air marshals, secure cockpit doors, bomb sniffing dogs, etc.

You're so close to getting it, but I have a feeling you don't WANT to understand.