Bizarrely, you can travel from Canada to US by air but not by land

There have been all sorts of inconsistent and illogical rules established throughout this pandemic, but one particular howler that very few people seem to know about (including me, until today) is that it is in fact entirely possible to fly from Canada to the USA, even though land travel between the two countries is banned, a restiction that will remain in place until at least June 21st.
In fact, so few people seem to know about it that people who have done it suggest you book online, because if you try to book by phone you may well get refused because many agents don't even know about it. In some cases, people only found out about it from US border security guards who had to refuse land access to Canadian travellers.
It's a bizarre situation.
Another such anomaly is that Americans can travel through Canada (by land) if they are in transit to Alaska. In this way, several Americans have been seen wandering around the tourist areas of Banff and Jasper, totally ignoring social distancing and mask-wearing protocols in that peculiarly self-confident American way, much to the alarm of the hunkered-down locals.