Visa-exempt business travellers, workers, students, and tourists from countries other than the United States will require an Electronic Travel Authorization (eTA) to fly or transit through Canada by air as of September 29, 2016. The leniency period which allows travel without an eTA ends on that date. Without an eTA, travellers will not be able to board their flight bound for Canada. Travellers should apply well in advance, as it may not be possible to obtain one on the date of travel.