Also known as motion sickness, travel sickness is a common disorder where people experience nausea, headaches and dizziness when travelling by boat, plane, train or car. It can also occur when riding amusement park rollercoasters and rides. The disorder comes from the inner ear, where it sends the brain different signals to what the eyes can see. The confused messages make you feel dizzy and unwell. Relieve travel sickness with a variety of medications.