Oh lord, why do people insist on talking about things they haven't a clue about.
Owenc, the SWF flight was on the brand new 737 MAX, the aircraft that we are currently talking about. PVD was operated by a regular 737-800, some of which are ETOPS approved in the Norwegian fleet (they'd use the ETOPS approved ones for the TATL flights naturally.)
In months to come, they will only use 737 MAX on the routes, and the regular 737-800NG only in Europe.