Sharp objects split cleanly between the cabin and the hold. Scissors with blades under four inches, disposable razors, nail clippers and tweezers pass the checkpoint. Knives of any length, loose razor blades, box cutters and most tools over seven inches do not, and belong in a checked bag, sheathed or wrapped.The officer at the tray has the final say on anything unusual, and enforcement varies by airport. Each item page below gives the carry-on and checked verdict, the exact length rule where one exists, and what travelers report actually happens at screening.