You cannot carry a standard Leatherman tool in your carry-on luggage on international flights because almost all models contain blades or sharp pliers that are prohibited by the TSA and international aviation authorities. If you attempt to bring one through security, it will be confiscated. The only exception is the Leatherman Style PS, which is specifically designed without a blade to be "TSA-compliant," though even this model is often at the "discretion" of individual security agents who may still deem the pliers a threat. For all other models like the Wave, Charge, or Surge, you must pack them in your checked luggage. When traveling to countries with strict "carry" laws (like the UK or Japan), be aware that even having a locking-blade multitool in your pocket after you leave the airport can sometimes lead to legal issues, so it is best to keep your Leatherman stored in your bag until you are at your destination.