A permanent resident card is necessary to board a plane destined for Canada, particularly for those persons who possess a passport that is associated with a requirement to apply for a visitor visa before entering Canada Renewing a permanent resident card requires precision when describing your physical presence in Canada (i.e. The amount of days in Canada the minimum of which must be 730).

Some exceptions to the minimum 730 days inside of Canada include being employed full time for a Canadian based company outside of Canada, and accompanying a Canadian citizen spouse who is outside of Canada.
Legal advice may be necessary if relying on the Canadian citizen spouse or Canadian company exemption; a mere declaration that you accompanied your Canadian citizen spouse, or were employed full time by a Canadian employer is insufficient.

It is not advisable to leave Canada without a permanent resident card that is valid for re-entry to Canada. The failure to possess a non-expired permanent resident card may necessitate the need to file a travel document application at a Canadian visa office. Such travel document applications are not issued as of right. Rather, a badly prepared travel document application can trigger the loss of permanent resident status. The loss of permanent resident status would necessitate an appeal at the Immigration Refugee Board (Appeal Division), a court-like tribunal. It is strongly suggested that you hire an immigration lawyer to prepare a travel document application. Permanent resident applications if characterized by a passport with many entry and exit stamps would benefit from legal advice as well.