Really doubt if you can travel from US to Canada for landing. According to the page:
https://www.canada.ca/en/immigratio...s-covid19/travel-restrictions-exemptions.html
You can travel to and may be permitted to enter Canada if you’re a
- Canadian citizen
- Canadian permanent resident
- person registered under Canada’s Indian Act
- protected person
- foreign national who is coming for an essential (non-discretionary) purpose from the United States (U.S.)
- foreign national who is coming for an essential (non-discretionary) purpose from a country other than the U.S. and are exempt from the travel restrictions (see Exemptions to the travel restrictions for more information)
Notice the difference of the last two bullet points. It means only foreign national who comes from countries except U.S. has travel restriction exemptions. The following part further elaborates the exemption:
The following people may travel to Canada for an essential (non-discretionary) purpose from a country other than the U.S.:
The 3rd bullet point is actually CoPR holders approved on or before Mar 18.
So, what I get from this web page is that for CoPR holder, you can only come to Canada from countries except US, and the approval date on CoPR is on or before Mar 18. If you want to come to Canada from U.S., you MUST show to CBSA officers that your travel is essential, which doesn't include immigration service.