Permanent residents must have a valid PR card or permanent resident travel document (PRTD) to return to Canada by plane, train, bus or boat. Without one, you may not be able to board flight.
Your PR card needs to be valid when you show it. If your card expires, you will have to apply for a new one. To be eligible for a PR Card renewal, you must be physically present in Canada for at least 730 days out of the five-year period.