A stowaway is someone who hides on a train, bus, plane, or ship in the hope of traveling for free. There are a number of reasons to stowaway on board a craft, ranging from illegal immigration to a dare. As a general rule, being a stowaway can be extremely dangerous, and it can also carry serious legal repercussions if the stowaway is caught, especially on aircraft.
Stowing away is probably almost as old as commercialized traffic. Stowaways were certainly documented on Ancient Greek and Roman ships, and they included escaping slaves, people avoiding military service, and people who just wanted adventure. Stowaways also weren't limited to people; rats, for example, famously spread the Black Plague by stowing away on ships, and animal stowaways continue to be a problem throughout the world.
Some historical stowaways managed to make their way safely to their destination and even profit from the endeavor. A handful of people who made a new start in the Americas, for example, were stowaways on board ship, and many of these people were helped by regular passengers who smuggled them food and hid them from the officers of the ship.
The dangers of being a stowaway vary, depending on the type of transit used. At a minimum a stowaway risks being caught and thrown off or forced to pay a full fare. Many stowaways also expose themselves to physical risks; on trains, for example, people are injured every year by trying to hop on or off moving trains, and some of these injuries are quite severe. Aircraft stowaways have frozen to death in landing gear, while stowaways on ships have starved to death from lack of food during long journeys.
Because being a stowaway is dangerous, most people only attempt it when they feel that they have no other choice. Refugees from wars, for example, may stowaway after being denied refugee status, or immigrants may stowaway because they cannot afford the fare to travel to a new country. Criminals have also been known to attempt to stowaway while evading justice.
Some people also romanticize the idea of stowing away, and they may attempt it on a dare or for fun. This is not advised, because thanks to sweeping changes in transportation law after 11 September, many companies have severely cracked down on stowaways, making the practice extremely difficult and thereby much more dangerous. If caught, a stowaway could potentially be treated as a terrorist, and find him or herself in a very sticky situation.