If I remember correctly, ETOPS is the permission for a twin engined aircraft to fly more than 60 minutes single engined from an alternative airport. Does anyone know if Kevlavik and Gander would fit a flightplan in that respect? If not, then these oceanic Caravelle flights are remarkable, for the twin engine 60 minute rule dates back to the '50s.
I have an idea that the old rules were 90 mins from an alternate for twin engined aircraft.
In Etops times, several operators have used non ETOPS aircraft on North Atlantic ops. using a northern route to have Keflavik, Narssaraq, and Gander as alternates.
In a previous life, the company I worked for bid for a TNT route to JFK using A300-B4s, but an Icelandic airline got the contract.