http://www.cic.gc.ca/english/newcomers/about-pr.asp?_ga=1.165502655.1696883959.1477107788
Permanent residents (PRs) of Canada must carry and present their valid PR card or permanent resident travel document (PRTD) when boarding a flight to Canada, or travelling to Canada on any other commercial carrier. If you do not carry your PR card or PRTD, you may not be able to board your flight, train, bus or boat to Canada.
It is your responsibility to ensure that your PR card is still valid when you return from travel outside Canada, and to apply for a new PR card when your current card expires. If your PR card expires, it does not mean you have lost permanent resident status.
CIC说的很明确,枫叶卡或旅行文件是乘坐营业性交通工具去加拿大必须的证件,因为没有枫叶卡或旅行文件,你上不来飞机船和火车。但是不包括私人交通工具。