In 2013, the TSA went back on its chief's decision to allow small blades and other commonly considered "safe items" into carry-on luggage after pressure from scared airline workers and passengers.
Currently, full length knitting needles, 4" metal tipped scissors, and screwdrivers up to 7" long are allowed in carry-on. There is no extra danger that a 2.3" folding pocket knife blade could create. People carry these small knives for use as a tool against the problems that regularly come up in travel and on the road, not for use as a weapon.
Sign this to show you are an American that does not fear imaginary threats.