ETA is a per-screening program this is being taken off through 2015 and 2016. Until this time, visa-absolved remote nationals scanning for passage to Canada have not been systematically screened for admissibility until they touch base at a Canadian Port of section.
The ETA is presently compulsory for most site traveler from nations whose residents do now not require a TRV who are entering Canada through air.
Civilian of visa-excluded countries planning to go to Canada via air are required to have connected for an obtained an Electronic Travel Authorization (ETA) before their flight to Canada.
Special cases to this include citizens of the United States, who don’t require a TRV or an Electronic Travel Authorization (ETA), and green Card holders in the United States, who require an ETA to come to Canada, regardless of their nationality.