From:
International aviation: United States - Transport
Accession of Norway and Iceland
Norway and Iceland accession to the Air Transport Agreement as amended by the Protocol is provisionally applied as from 21 June 2011.
Article 18 (5) of the EU-US Air Transport Agreement confirms both Parties' goal of "maximising the benefits for consumers, airlines, labour and communities on both sides of the Atlantic by extending this Agreement to include third countries". Ensuring that the bilateral character of the EU-US Air Transport Agreement is maintained, the parties signed on 21 June 2011 two agreements:
Air Transport Agreement between the United States of America, of the first part, the European Union and its Member States, of the second part, Iceland, of the third part, and the Kingdom of Norway, of the fourth part is provisionally applied from 21 June 2011.
Ancillary Agreement between the European Union and its Member States, of the first part, Iceland, of the second part, and the Kingdom of Norway, of the third part, on the application of the Air Transport Agreement between the United States of America, of the first part, the European Union and its Member States, of the second part, Iceland, of the third part, and the Kingdom of Norway, of the fourth part is provisionally applied from 21 June 2011.
These Agreements ensure a consistent regulatory framework for flights between the US and the single aviation market in the EU – including Iceland and Norway.
Switzerland has not (yet) acceded to the treaty although they may. Can't see much in it for Swiss companies so there is little pressure to do so. Swiss' owner may have different views, but they seem content to have LX cover the market.
The 'flag of convenience' for Norwegian is limited to US-EU/IS routes, and any other market where the EU will have negotiated similar provisions. IMHO the European Commission hates with a passion the ownership and control provisions in existing air services agreements - and sees nothing wrong with Norwegian airlines acting in this way.