I am stealing this from the London reddit but it's kind of cool and patriotic, I have seen runners, walkers and cyclists take routes which basically draw pictures but this is the first time I have seen someone do it with a plane.
The pilot had pretty good precision. https://www.reddit.com/r/londonontario/comments/1iiw5q2/interesting_flight_path_over_london_on_february_5/
There is a lot of air traffic over this area in Ontario, many US to US flights pass over Ontario for the shortest route, many of the international flights bound to the US and vice versa also fly over our land mass every day though at heights well above the operational limits of this plane. At these lower regions air traffic is sparse, mostly smaller aircraft operating under visual flight rules.