Long story short, tiger teams have smuggled everything from .22 zip guns to field-stripped machine pistols and ammunition onto commercial jets. That includes mutilating grenades, door-popping explosives and EMP devices that can switch off a jumbo jet like a light bulb in a walk-in closet. It's just as well that legally dead operators aren't known for whistleblowing, because nobody would ever get on an airplane again. Nobody with half a clue has ever entertained the idea that box-cutters were the primary weapons used on 9/11, anyway.

That's just X-ray machines and walking through metal detectors barefoot. Cargo handling is a total nightmare. If it will physically fit into the hold and you have the money, you can get it aboard. By the time the throwers involved are found in a closet with their throats cut, the damage will be done and FAA people will be checking rooftops for stray body parts.