juddles

pmarrsouth and Milkman, as I had some time today I researched this thing. Just for fun

You are both correct in that in many definitions, the split between North and South America lies somewhere between Colombia and Panama, even though Panama is in physical terms south of Colombia. (the exact line/split is fought over - from the Darien to the Panama canal. (It is not the simple modern country boundaries) Other definitions place Panama in Central America. The whole concept of "Central America" being a new thing. Others place it in South America...
So as such I bow to your somewhat supported assertion that Panama can be viewed as in "North America". But I also, as I love to argue (to learn, not to be a pain), also assert that the context of this argument is important. This is in a frequent flyer forum. We are talking airlines, and lounges, not geography. I doubt that most flyers think of Panama and thus Copa as a "North American' airline. You will not find COPA in Flyertalk's North American section....