When you’re travelling abroad, whether for vacation or more permanent plans, it’s important to stay informed about the documents you’ll need. Depending on your nationality, the travel documents required to fly to Canada may have just changed.
VISA-EXEMPT TRAVELLERS NOW REQUIRE eTA

The Government of Canada has new entry requirements in effect. Visa-exempt foreign nationals now need an Electronic Travel Authorization (eTA) if they are flying to or through Canada. For a complete list of visa-exempt countries, visit the Government of Canada website.

U.S. citizens and permanent residents are exempt though. So if you are a U.S. citizen or permanent resident you do not need an eTA, just your passport or Green Card.

As before, foreign nationals from countries that are not visa-exempt will need a valid Visitor’s Visa to enter the country. Canadian citizens and permanent residents cannot apply for an eTA.

Citizens, including those with dual citizenship, will have to present their Canadian passport to enter the country. Similarly, permanent residents must present their valid PR card or permanent resident travel document (PRTD). Please be aware that if your PR card has expired, you have not lost your status. However, you do need to apply for a new one. Especially if you are planning on travelling outside Canada.
  Canadim are experts in Canadian immigration law. Canadian immigration policies and practices change all the time. It’s our job to know what changes are coming, but we recognize that you’re hugely invested in the process too. That’s why we do our best to keep you informed about recent Canadian Immigration news. I