Then, over the border the finished, packaged products go, tariff-free, under the auspices of NAFTA.
Separately, I'll mention that I've heard commentary on Canadian news to the effect that the Provincial and perhaps National governments provided assistance -- not taking an ownership stake; rather, direct financial assistance -- to Bombardier to aid in development of the jet.
To the extent that expected returns, financial and employment and whatever, are now leaving the Province and Canada, this leaves those governments out in the cold and deprived of expected returns. I don't know all the details of this, and perhaps what I heard was biased, but it was described at length and very critical e.g. of the governments not having built greater assurances into the aid they provided.