If you check in online with Air Canada the form asks if you are taking a bicycle. If you check in at the airport and they see a large regular-looking suitcase they don't ask. They weigh it and put it on the belt. It means a longer line and a longer wait at the airport, but it also means it just goes through.

(That is my experience from a year or so ago, before Air Canada started charging for every item of baggage. This year I flew WestJet to Florida, and both check-in woman and the US customs official were curious about the whole concept of a bicycle that fitted inside a regular suitcase. Confusingly, the case weighed in at 45 pounds on the way out, and 51 pounds on the way back, with almost exactly the same stuff inside it. They didn't charge excess baggage on the way back, although they presumably had the right to do so.)