Is a 4 inch knife significantly less dangerous than longer knives?<p>A shiv is a short knife, and razor blades are banned from airplane carry-ons.<p>They try to discern between common objects being weapons and it becomes situational, except for cooking utensils. For some reason hammers aren’t seen as a weapon because some people don’t know about maces or clubs.<p>Sorry kids, your dad can’t cut the turkey because we aren’t allowed to have a long enough knife.