The problem wasn't the knife regulation. We should allow such tiny knives on planes. They're harmless. You can go to a fancy restaurant in the airport and get served steak with a steak knife. You can bring an object with a glass piece in it, smash the glass once you're passed security, and have a small bladed weapon that way. You can bring in dull metal and file into a sharp edge on the tile of the floor of the family bathroom prison shive style. It's trivially easy to get such a small bladed weapon inside the security cordon. Hell, some people have finger nails that are more dangerous than those knives.

The real impactful change after 9/11 was reinforcing the cockpit doors, and putting in regulations requiring them to remain closed and locked during flight. That was the real impactful change. The TSA's just security theater.

Both you and your grandpa were right. But you both missed the real solution.