to rescind that ruling and say small knives, any knives, are not allowed on planes. >> reporter: new york senator chuck schumer joins unions representing pilots, flight attendants and federal air marshals in publicly opposing the plan. delta airlines' ceo also expressed his objection in a letter sent to the agency. saying the change will, quote, add little value to the customer security process flow in relation to the additional risk for our cabin staff and customers." under the tsa's new policy, knives with blades shorter than 2.36 inches, and less than a half an inch wide, will be allowed, provided the blade does not lock in place. larger knives, razor blades, and box cutters, are still banned. tsa administrator john pistol says the change will allow screeners to focus on things that could bring down an aircraft, like bombs. >> the key factor for me is that