Banner add from Norwegian booking page
Please note that all of Norwegian’s long-haul routes between the US and the UK are operated by Norwegian Air Shuttle, which has all the necessary permits to fly to and from the US. Our subsidiary is still waiting for an approval from the US Department of Transportation (DOT), but this doesn't affect our operations.
The above is cut & paste from the headline on the Norwegiam.com home page
These will be the same aircraft & crews using the same procedures, manuals, maintenance facilities, operational oversight, the only difference is that they are operated by NAS rather than NAI
DOT heel dragging at the behest of union/airline lobbying does not paint the US in a good light.