Highjacking, also known as aircraft piracy, is the illegal act of taking control of an aircraft by force or threat of force. It is usually done by hijackers who demand to be taken to a certain destination or to have certain demands met. The term 'highjack' comes from the verb 'COMMANDEER, ' which means to take possession of something without permission. Commandeering an aircraft is a serious crime and can result in severe penalties.