Knives, razors and cutlery on a plane
Knives and folding blades
At a US checkpoint, TSA does not permit kitchen knives, pocket knives or Swiss Army knives with blades in carry-on baggage. Their size does not change that rule. Put them in checked baggage with the edge sheathed or securely wrapped. Plastic cutlery and round-bladed, blunt butter knives have a separate TSA exception.
Razors depend on the blade housing
A disposable or cartridge razor can go in carry-on when its blade remains enclosed in the head. Remove the blade from a safety razor before the checkpoint; loose blades and straight razors belong in checked baggage. Check the contents of a shaving case rather than judging every razor by its handle.
Scissors and cigar cutters
TSA permits scissors in carry-on only when each blade is shorter than 4 inches from the pivot. Larger scissors go in checked baggage. A cigar cutter is generally permitted, but TSA recommends checking it because an officer may reject a sharp cutter at screening. If a sewing kit also contains needles, see the pins and needles guide.
Check every piece of cutlery
Ordinary forks, spoons and chopsticks have their own permitted entries. A travel cutlery case can also contain a knife, so inspect every piece before packing. A blade in the set follows the knife rule even when the other utensils may travel in carry-on.
Source: TSA: complete item list.