I do believe that a child born in Canada is a Canadian. There was a Ugandan woman flying to the US (Boston) and gave birth in Canadian airspace. The news reported that the child will be Canadian.
(this is somewhat contradictory to the last episode of Bones that I saw where they arrested a guy on a plane seconds before it landed in China because they claimed that as long as the plane hadn't touched the soil in China, it is still within US jurisdiction.)