The airline had been given protection from bankruptcy by courts in Oslo and Ireland while it underwent reconstruction.
The process has meant the airline closing its long-haul arm and returning to its roots as a short-haul carrier, as well as shedding thousands of staff.
Norwegian first sought protection from creditors last November after an appeal to the Norwegian government for a cash injection was ignored.
A period in which creditors were able to appeal the process has now expired.
The airline said: “At the expiry of the appeal period no appeals have been filed and consequently the Reconstruction Plan is final and binding.
“The company is consequently determined to complete the reconstruction process on 26 May 2021.”
In March, a consortium of investors, including former Norwegian chief executive Bjorn Kjos revealed plans to re-launch low-cost long-haul flights.
The venture, Norse Atlantic Airways, will use some ex-Norwegian aircraft.
