I think a great list of destinations for Summer 2020 from KEF would be.
I agree. They should fly to YYZ and YUL. Wow was able to fly daily to YUL, often on A321, so the passenger demand was probably there. And as opposed to the US with Norwegian, Canada isn't served by any ULCC for transatlantic flight with connections (except Level which doesn't have a lot of connections, if any).
Would Warsaw work despite Wizz Air and their very cheap tickets to Reykjavík?
The thing with WAW is that a lot of young Poles need to travel between the US/Canada on a budget so in my mind WAW works well for the sake of transit passengers from YYZ and DTW who have no low fare options. Agreed all 4 options I chose in North America give PLAY pricing power in those markets.
I bet of you went to Warsaw Krakow or Katowice and asked the youth where they would want to go in USA, I think these 4 would be 99 percent of answers: NYC CHI LAX MIA
Airlines flown: A3, AA, AC, AF, AM, BA, B6, CA, CO, CX, DL, EA, EL, IB, LH, MI, MQ, NH, NW, NZ, OU, PE, QF, S4, SQ, TP, UA, US, VS, WE, WN
2019: CX BOS-HKG, WE HKG-HKT, CA HKT-PEK-EWR, B6 EWR-BOS