Canada - Entry Requirements
Transport companies, such as air, rail, and bus services, are required to ensure that all passengers can produce valid, universally accepted travel documents. Transport companies, especially international airlines, may be fined if they carry improperly documented travellers and are often liable to return those passengers to their point of origin.
A Certificate of Canadian Citizenship is not a travel document. A Canadian passport is the only reliable and universally accepted travel and identification document available to Canadians for the purpose of international travel. Canadian citizens returning to Canada who present other documents, such as a Certificate of Canadian Citizenship, birth certificate, provincial driver's license, or foreign passport, instead of a Canadian passport, may face delays or be denied boarding by transport companies.