Jurisdiction over aircraft and ships is based on the principle that a state exercises complete and exclusive sovereignty over the airspace above its territory and territorial waters (Chicago Convention, 1944). For aircraft, the state of registration has jurisdiction over offences committed on board while in flight (Tokyo Convention, 1963), which also grants the captain authority to use reasonable force and obliges states to act against hijacking. At sea, the flag state generally has exclusive jurisdiction over vessels on the high seas, subject to specific exceptions under international law (e.g. piracy, slavery, unauthorised broadcasting).