I have a valid canadian passport and hong kong resident's ID card and home return card. I will be traveling from Toronto to Hong Kong in October. I am thinking to use my HK resident's home return card to get into Shenzhen, then take the plane from Shenzhen to Shanghai for a few days, do I need a visa to fly from Shenzhen to Shanghai? Can I use my home return card to board the plane? Does anyone know? Thank you.