Often interpreters need to travel long distances to attend an event. In some cases and especially for rarer languages, this may involve international travel. We would always aim too have interpreters travel out the evening before so they travel outside their normal working day. However, sometimes flight schedules make this impossible so they need to travel during the working day which means they cannot accept any other job. The travel day, charged at half their daily work fee, is to compensate for any other work they must turn down to attend your event.