I doubt plastic containers will be allowed in the near future, given that Air Canada is going EXCLUSIVELY to the slimmer jets that have NO HEATED CARGO. Exactly how does one insulate a plastic box? LOL!
3/4" cardboard?? Holy smokes, do they even make it that thick? I get my boxes now custom made FROM the fish transport industry and they are the THICKEST available and they are no where near 3/4" thick. My styrofoam is though.