Pistole said in a three-month period last year, the TSA seized 47 small knives from passengers at Los Angeles International Airport alone. But the knives presented little threat to the plane, he said.

"Our greatest concern, the greatest risk, is non-metalic IEDs, whether that's explosive, whether that's (an) electronic initiator or a chemical initiator, whatever that may be. That's what I want I security officers to focus on," he said.