The CBS News had a feature this morning about Norwegian and how the airline is facing obstacles trying to further enter the US market.
The airline is trying to get something called a “Foreign Air Carrier Permit” and other airlines are lobbying against this.
You can access CBS News video here.
Conclusion
Norwegian was first trying to use Thai cabin crews and pilots based out in Thailand to work on at least some of the transatlantic flights. I guess that they have decided to back away from this. The airline is now trying to open a flight attendant base in the US that would staff these flights.