A classic Tip of the Week from June 13, 2004, originally re-published February 2, 2016
If you want to keep your Swiss army knife, nail scissors, or lacrosse sticks while traveling by air, don't pack them in your carry-on luggage. In a season of extra vigilance by the security personnel in airports around the country, you can expect any verboten object to be removed from your carry-on bags and confiscated. (Some airports will allow you to mail the item back to yourself--at your expense--but not all offer this service.)
For the most up-to-date list of what you can and cannot carry in your luggage, refer to the TSA's list of Permitted and Prohibited Items. Because while well-organized luggage can help make travel more enjoyable, only well-planned packing can help keep your trips and your possessions safe.